rocm-systems/projects/rocprofiler-systems/source/lib/omnitrace/library/sampling.cpp

// MIT License
//
// Copyright (c) 2022 Advanced Micro Devices, Inc. All Rights Reserved.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.

#include "library/sampling.hpp"
#include "core/common.hpp"
#include "core/components/fwd.hpp"
#include "core/config.hpp"
#include "core/debug.hpp"
#include "core/locking.hpp"
#include "core/state.hpp"
#include "core/utility.hpp"
#include "library/components/backtrace.hpp"
#include "library/components/backtrace_metrics.hpp"
#include "library/components/backtrace_timestamp.hpp"
#include "library/ptl.hpp"
#include "library/runtime.hpp"
#include "library/thread_data.hpp"
#include "library/thread_info.hpp"
#include "library/tracing.hpp"
#include "library/tracing/annotation.hpp"

#include <timemory/backends/papi.hpp>
#include <timemory/backends/threading.hpp>
#include <timemory/components/data_tracker/components.hpp>
#include <timemory/components/macros.hpp>
#include <timemory/components/papi/extern.hpp>
#include <timemory/components/papi/papi_array.hpp>
#include <timemory/components/papi/papi_vector.hpp>
#include <timemory/components/timing/backends.hpp>
#include <timemory/components/trip_count/extern.hpp>
#include <timemory/macros.hpp>
#include <timemory/math.hpp>
#include <timemory/mpl.hpp>
#include <timemory/mpl/quirks.hpp>
#include <timemory/mpl/type_traits.hpp>
#include <timemory/operations.hpp>
#include <timemory/sampling/allocator.hpp>
#include <timemory/sampling/sampler.hpp>
#include <timemory/storage.hpp>
#include <timemory/units.hpp>
#include <timemory/utility/backtrace.hpp>
#include <timemory/utility/demangle.hpp>
#include <timemory/utility/procfs/maps.hpp>
#include <timemory/utility/types.hpp>
#include <timemory/variadic.hpp>

#include <array>
#include <chrono>
#include <condition_variable>
#include <csignal>
#include <cstring>
#include <ctime>
#include <initializer_list>
#include <mutex>
#include <regex>
#include <sstream>
#include <string>
#include <type_traits>

#include <pthread.h>
#include <signal.h>

namespace tim
{
namespace math
{
template <typename Tp, typename Up>
TIMEMORY_INLINE Tp
plus(Tp&& _lhs, const Up& _rhs)
{
    Tp _v = _lhs;
    plus(_v, _rhs);
    return _v;
}
}  // namespace math
}  // namespace tim
namespace omnitrace
{
namespace sampling
{
using ::tim::sampling::dynamic;
using tim::sampling::timer;

using hw_counters               = typename component::backtrace_metrics::hw_counters;
using signal_type_instances     = thread_data<std::set<int>, category::sampling>;
using sampler_running_instances = thread_data<bool, category::sampling>;
using bundle_t =
    tim::lightweight_tuple<component::backtrace_timestamp, component::backtrace,
                           component::backtrace_metrics>;
using sampler_t              = tim::sampling::sampler<bundle_t, dynamic>;
using sampler_instances      = thread_data<sampler_t, category::sampling>;
using sampler_init_instances = thread_data<bundle_t, category::sampling>;
}  // namespace sampling
}  // namespace omnitrace

OMNITRACE_DEFINE_CONCRETE_TRAIT(prevent_reentry, sampling::sampler_t, std::true_type)

OMNITRACE_DEFINE_CONCRETE_TRAIT(provide_backtrace, sampling::sampler_t, std::false_type)

OMNITRACE_DEFINE_CONCRETE_TRAIT(buffer_size, sampling::sampler_t,
                                TIMEMORY_ESC(std::integral_constant<size_t, 1024>))

namespace omnitrace
{
namespace sampling
{
namespace
{
using sampler_allocator_t = typename sampler_t::allocator_t;

auto&
get_sampler_allocators()
{
    static auto _v = std::vector<std::shared_ptr<sampler_allocator_t>>{};
    return _v;
}

std::set<int>
configure(bool _setup, int64_t _tid = threading::get_id());

void
configure_sampler_allocator(std::shared_ptr<sampler_allocator_t>& _v)
{
    if(_v) return;

    OMNITRACE_SCOPED_SAMPLING_ON_CHILD_THREADS(false);
    OMNITRACE_SCOPED_THREAD_STATE(ThreadState::Internal);

    _v = std::make_shared<sampler_allocator_t>();
    _v->reserve(config::get_sampling_allocator_size());
}

void
configure_sampler_allocators()
{
    auto& _allocators = get_sampler_allocators();
    if(_allocators.empty())
    {
        // avoid lock until necessary
        auto_lock_t _alloc_lk{ type_mutex<decltype(_allocators)>() };
        if(_allocators.empty())
        {
            _allocators.resize(std::ceil(config::get_num_threads_hint() /
                                         config::get_sampling_allocator_size()));
            for(auto& itr : _allocators)
                configure_sampler_allocator(itr);
        }
    }
}

std::shared_ptr<sampler_allocator_t>
get_sampler_allocator()
{
    configure_sampler_allocators();

    auto& _allocators = get_sampler_allocators();

    OMNITRACE_SCOPED_THREAD_STATE(ThreadState::Internal);

    auto_lock_t _lk{ type_mutex<sampler_allocator_t>() };

    for(auto& itr : _allocators)
    {
        if(!itr) configure_sampler_allocator(itr);
        if(itr->size() < config::get_sampling_allocator_size()) return itr;
    }

    auto& _v = _allocators.emplace_back();
    configure_sampler_allocator(_v);
    return _v;
}

template <typename... Args>
void
thread_sigmask(Args... _args)
{
    auto _err = pthread_sigmask(_args...);
    if(_err != 0)
    {
        errno = _err;
        perror("pthread_sigmask");
        exit(EXIT_FAILURE);
    }
}

template <typename Tp>
sigset_t
get_signal_set(Tp&& _v)
{
    sigset_t _sigset;
    sigemptyset(&_sigset);
    for(auto itr : _v)
        sigaddset(&_sigset, itr);
    return _sigset;
}

template <typename Tp>
std::string
get_signal_names(Tp&& _v)
{
    std::string _sig_names{};
    for(auto&& itr : _v)
        _sig_names += std::get<0>(tim::signals::signal_settings::get_info(
                          static_cast<tim::signals::sys_signal>(itr))) +
                      " ";
    return (_sig_names.empty()) ? _sig_names
                                : _sig_names.substr(0, _sig_names.length() - 1);
}

unique_ptr_t<sampler_t>&
get_sampler(int64_t _tid = threading::get_id())
{
    static auto& _v = sampler_instances::instances();
    return _v.at(_tid);
}

unique_ptr_t<bundle_t>&
get_sampler_init(int64_t _tid = threading::get_id())
{
    static auto& _v = sampler_init_instances::instances();
    if(!_v.at(_tid)) _v.at(_tid) = unique_ptr_t<bundle_t>{ new bundle_t{} };
    return _v.at(_tid);
}

unique_ptr_t<bool>&
get_sampler_running(int64_t _tid)
{
    static auto& _v = sampler_running_instances::instances(construct_on_init{}, false);
    return _v.at(_tid);
}

auto&
get_duration_disabled()
{
    static auto _v = std::atomic<bool>{ false };
    return _v;
}

auto&
get_is_duration_thread()
{
    static thread_local auto _v = false;
    return _v;
}

auto&
get_duration_cv()
{
    static auto _v = std::condition_variable{};
    return _v;
}

auto&
get_duration_mutex()
{
    static auto _v = std::mutex{};
    return _v;
}

auto&
get_duration_thread()
{
    static auto _v = std::unique_ptr<std::thread>{};
    return _v;
}

auto
notify_duration_thread()
{
    if(get_duration_thread() && !get_is_duration_thread())
    {
        std::unique_lock<std::mutex> _lk{ get_duration_mutex(), std::defer_lock };
        if(!_lk.owns_lock()) _lk.lock();
        get_duration_cv().notify_all();
    }
}

void
stop_duration_thread()
{
    if(get_duration_thread() && !get_is_duration_thread())
    {
        notify_duration_thread();
        get_duration_thread()->join();
        get_duration_thread().reset();
    }
}

void
start_duration_thread()
{
    static std::mutex            _start_mutex{};
    std::unique_lock<std::mutex> _start_lk{ _start_mutex, std::defer_lock };
    if(!_start_lk.owns_lock()) _start_lk.lock();

    if(!get_duration_thread() && config::get_sampling_duration() > 0.0)
    {
        // we may need to protect against recursion bc of pthread wrapper
        static bool _protect = false;
        if(_protect) return;
        _protect   = true;
        auto _now  = std::chrono::steady_clock::now();
        auto _end  = _now + std::chrono::nanoseconds{ static_cast<uint64_t>(
                               config::get_sampling_duration() * units::sec) };
        auto _func = [_end]() {
            thread_info::init(true);
            threading::set_thread_name("omni.samp.dur");
            get_is_duration_thread() = true;
            bool _wait               = true;
            while(_wait)
            {
                _wait = false;
                std::unique_lock<std::mutex> _lk{ get_duration_mutex(), std::defer_lock };
                if(!_lk.owns_lock()) _lk.lock();
                get_duration_cv().wait_until(_lk, _end);
                auto _premature = (std::chrono::steady_clock::now() < _end);
                auto _finalized = (get_state() == State::Finalized);
                if(_premature && !_finalized)
                {
                    // protect against spurious wakeups
                    OMNITRACE_VERBOSE(
                        2, "%sSpurious wakeup of sampling duration thread...\n",
                        tim::log::color::warning());
                    _wait = true;
                }
                else if(_finalized)
                {
                    break;
                }
                else
                {
                    get_duration_disabled().store(true);
                    OMNITRACE_VERBOSE(1,
                                      "Sampling duration of %f seconds has elapsed. "
                                      "Shutting down sampling...\n",
                                      config::get_sampling_duration());
                    configure(false, 0);
                }
            }
        };

        OMNITRACE_VERBOSE(1, "Sampling will be disabled after %f seconds...\n",
                          config::get_sampling_duration());

        OMNITRACE_SCOPED_SAMPLING_ON_CHILD_THREADS(false);
        get_duration_thread() = std::make_unique<std::thread>(_func);
        _protect              = false;
    }
}

auto&
get_offload_file()
{
    static auto _v = config::get_tmp_file("sampling");
    return _v;
}

locking::atomic_mutex&
get_offload_mutex()
{
    static auto _v = locking::atomic_mutex{};
    return _v;
}

using sampler_bundle_t = typename sampler_t::bundle_type;
using sampler_buffer_t = tim::data_storage::ring_buffer<sampler_bundle_t>;

void
offload_buffer(int64_t _seq, sampler_buffer_t&& _buf)
{
    OMNITRACE_REQUIRE(get_use_tmp_files())
        << "Error! sampling allocator tries to offload buffer of samples but "
           "omnitrace was configured to not use temporary files\n";

    // use homemade atomic_mutex/atomic_lock since contention will be low
    // and using pthread_lock might trigger our wrappers
    auto  _lk   = locking::atomic_lock{ get_offload_mutex() };
    auto& _file = get_offload_file();

    OMNITRACE_REQUIRE(_file)
        << "Error! sampling allocator tried to offload buffer of samples but the "
           "offload file does not exist\n";

    OMNITRACE_VERBOSE_F(2, "Offloading %zu samples for thread %li to %s...\n",
                        _buf.count(), _seq, _file->filename.c_str());
    auto& _fs = _file->stream;

    OMNITRACE_REQUIRE(_fs.good())
        << "Error! temporary file for offloading buffer is in an invalid state\n";

    _fs.write(reinterpret_cast<char*>(&_seq), sizeof(_seq));
    auto _data = std::move(_buf);
    _data.save(_fs);
    _data.destroy();
    _buf.destroy();
}

auto
load_offload_buffer()
{
    auto _data = std::map<int64_t, std::vector<sampler_buffer_t>>{};
    if(!get_use_tmp_files())
    {
        OMNITRACE_WARNING_F(
            2, "[sampling] returning no data because using temporary files is disabled");
        return _data;
    }

    // use homemade atomic_mutex/atomic_lock since contention will be low
    // and using pthread_lock might trigger our wrappers
    auto  _lk   = locking::atomic_lock{ get_offload_mutex() };
    auto& _file = get_offload_file();
    if(!_file)
    {
        OMNITRACE_WARNING_F(
            0, "[sampling] returning no data because the offload file no longer exists");
        return _data;
    }

    auto& _fs = _file->stream;

    _fs.close();
    _file->open(std::ios::binary | std::ios::in);

    if(!_fs)
    {
        OMNITRACE_WARNING_F(0, "[sampling] %s failed to open", _file->filename.c_str());
    }

    while(!_fs.eof())
    {
        int64_t _seq = 0;
        _fs.read(reinterpret_cast<char*>(&_seq), sizeof(_seq));
        if(_fs.eof())
        {
            OMNITRACE_VERBOSE_F(2, "[sampling] No more samples found in file...\n");
            break;
        }
        sampler_buffer_t _buffer{};
        _buffer.load(_fs);
        OMNITRACE_VERBOSE_F(2, "[sampling] Loading %zu samples for thread %li...\n",
                            _buffer.count(), _seq);
        _data[_seq].emplace_back(std::move(_buffer));
    }
    _file.reset();

    return _data;
}

std::set<int>
configure(bool _setup, int64_t _tid)
{
    const auto& _info         = thread_info::get(_tid, SequentTID);
    auto&       _sampler      = sampling::get_sampler(_tid);
    auto&       _running      = get_sampler_running(_tid);
    bool        _is_running   = (!_running) ? false : *_running;
    auto&       _signal_types = sampling::get_signal_types(_tid);

    OMNITRACE_CONDITIONAL_THROW(get_use_causal(),
                                "Internal error! configuring sampling not permitted when "
                                "causal profiling is enabled");

    OMNITRACE_SCOPED_SAMPLING_ON_CHILD_THREADS(false);

    auto&& _cpu_tids  = get_sampling_cpu_tids();
    auto&& _real_tids = get_sampling_real_tids();

    auto _erase_tid_signal = [_tid, &_signal_types](auto& _tids, int _signum) {
        if(!_tids.empty())
        {
            if(_tids.count(_tid) == 0)
            {
                OMNITRACE_VERBOSE(3, "Disabling SIG%i from thread %li\n", _signum, _tid);
                _signal_types->erase(_signum);
            }
        }
    };

    _erase_tid_signal(_cpu_tids, get_cputime_signal());
    _erase_tid_signal(_real_tids, get_realtime_signal());

    if(_setup && !_sampler && !_is_running && !_signal_types->empty())
    {
        if(get_duration_disabled()) return std::set<int>{};

        // if this thread has an offset ID, that means it was created internally
        // and is probably here bc it called a function which was instrumented.
        // thus we should not start a sampler for it
        if(_tid > 0 && _info && _info->is_offset) return std::set<int>{};
        // if the thread state is disabled or completed, return
        if(_info && _info->index_data->sequent_value == _tid &&
           get_thread_state() == ThreadState::Disabled)
            return std::set<int>{};

        (void) get_debug_sampling();  // make sure query in sampler does not allocate
        assert(_tid == threading::get_id());

        if(trait::runtime_enabled<backtrace_metrics>::get())
            backtrace_metrics::configure(_setup, _tid);

        // NOTE: signals need to be unblocked by calling function
        sampling::block_signals(*_signal_types);

        auto _verbose = std::min<int>(get_verbose() - 2, 2);
        if(get_debug_sampling()) _verbose = 2;

        OMNITRACE_DEBUG("Requesting allocator for sampler on thread %lu...\n", _tid);
        auto _alloc = get_sampler_allocator();

        OMNITRACE_DEBUG("Configuring sampler for thread %lu...\n", _tid);
        sampling::sampler_instances::construct(construct_on_thread{ _tid }, _alloc,
                                               "omnitrace", _tid, _verbose);

        _sampler->set_flags(SA_RESTART);
        _sampler->set_verbose(_verbose);

        if(_signal_types->count(get_realtime_signal()) > 0)
        {
            _sampler->configure(timer{ get_realtime_signal(), CLOCK_REALTIME,
                                       SIGEV_THREAD_ID, get_sampling_real_freq(),
                                       get_sampling_real_delay(), _tid,
                                       threading::get_sys_tid() });
        }

        if(_signal_types->count(get_cputime_signal()) > 0)
        {
            _sampler->configure(timer{ get_cputime_signal(), CLOCK_THREAD_CPUTIME_ID,
                                       SIGEV_THREAD_ID, get_sampling_cpu_freq(),
                                       get_sampling_cpu_delay(), _tid,
                                       threading::get_sys_tid() });
        }

        if(get_use_tmp_files())
        {
            auto _file = get_offload_file();
            if(_file && *_file) _sampler->set_offload(&offload_buffer);
        }

        static_assert(tim::trait::buffer_size<sampling::sampler_t>::value > 0,
                      "Error! Zero buffer size");

        OMNITRACE_CONDITIONAL_THROW(
            _sampler->get_buffer_size() !=
                tim::trait::buffer_size<sampling::sampler_t>::value,
            "dynamic sampler has a buffer size different from static trait: %zu instead "
            "of %zu",
            _sampler->get_buffer_size(),
            tim::trait::buffer_size<sampling::sampler_t>::value);

        OMNITRACE_CONDITIONAL_THROW(
            _sampler->get_buffer_size() <= 0,
            "dynamic sampler requires a positive buffer size: %zu",
            _sampler->get_buffer_size());

        for(auto itr : *_signal_types)
        {
            const char* _type  = (itr == get_realtime_signal()) ? "wall" : "CPU";
            const auto* _timer = _sampler->get_timer(itr);
            if(_timer)
            {
                OMNITRACE_VERBOSE(
                    2,
                    "[SIG%i] Sampler for thread %lu will be triggered %.1fx per "
                    "second of %s-time (every %.3e milliseconds)...\n",
                    itr, _tid, _timer->get_frequency(units::sec), _type,
                    _timer->get_period(units::msec));
            }
        }

        *_running = true;
        sampling::get_sampler_init(_tid)->sample();
        start_duration_thread();
        _sampler->start();
    }
    else if(!_setup && _sampler && _is_running)
    {
        OMNITRACE_DEBUG("Destroying sampler for thread %lu...\n", _tid);
        *_running = false;

        if(_tid == threading::get_id() && !_signal_types->empty())
        {
            sampling::block_signals(*_signal_types);
        }

        notify_duration_thread();

        if(_tid == 0)
        {
            block_samples();

            // this propagates to all threads
            _sampler->ignore(*_signal_types);

            // wait for the samples to finish
            auto _freq =
                std::max<double>(get_sampling_cpu_freq(), get_sampling_real_freq());
            auto _period = (1.0 / _freq) * units::sec;
            _period      = std::min<double>(_period, 1.0e9);  // max of 1 second
            std::this_thread::sleep_for(
                std::chrono::nanoseconds{ static_cast<int64_t>(_period) });

            for(int64_t i = 1; i < OMNITRACE_MAX_THREADS; ++i)
            {
                if(sampling::get_sampler(i)) sampling::get_sampler(i)->stop();
            }

            for(int64_t i = 1; i < OMNITRACE_MAX_THREADS; ++i)
            {
                if(sampling::get_sampler(i))
                {
                    sampling::get_sampler(i)->reset();
                    *get_sampler_running(i) = false;
                }
            }

            stop_duration_thread();
        }

        _sampler->stop();

        if(trait::runtime_enabled<backtrace_metrics>::get())
            backtrace_metrics::configure(_setup, _tid);

        OMNITRACE_DEBUG("Sampler destroyed for thread %lu\n", _tid);
    }

    return (_signal_types) ? *_signal_types : std::set<int>{};
}

void
post_process_perfetto(int64_t _tid, const bundle_t* _init,
                      const std::vector<bundle_t*>& _data);
void
post_process_timemory(int64_t _tid, const bundle_t* _init,
                      const std::vector<bundle_t*>& _data);
}  // namespace

unique_ptr_t<std::set<int>>&
get_signal_types(int64_t _tid)
{
    static auto& _v = signal_type_instances::instances();
    signal_type_instances::construct(construct_on_thread{ _tid },
                                     omnitrace::get_sampling_signals(_tid));
    return _v.at(_tid);
}

std::set<int>
setup()
{
    if(!get_use_sampling()) return std::set<int>{};
    return configure(true);
}

std::set<int>
shutdown()
{
    auto _v = configure(false);
    if(utility::get_thread_index() == 0) stop_duration_thread();
    return _v;
}

void
block_samples()
{
    trait::runtime_enabled<sampler_t>::set(false);
}

void
unblock_samples()
{
    trait::runtime_enabled<sampler_t>::set(true);
}

void
block_signals(std::set<int> _signals)
{
    if(_signals.empty()) _signals = *get_signal_types(threading::get_id());
    if(_signals.empty())
    {
        OMNITRACE_PRINT("No signals to block...\n");
        return;
    }

    OMNITRACE_DEBUG("Blocking signals [%s] on thread #%lu...\n",
                    get_signal_names(_signals).c_str(), threading::get_id());

    sigset_t _v = get_signal_set(_signals);
    thread_sigmask(SIG_BLOCK, &_v, nullptr);
}

void
unblock_signals(std::set<int> _signals)
{
    if(_signals.empty()) _signals = *get_signal_types(threading::get_id());
    if(_signals.empty())
    {
        OMNITRACE_PRINT("No signals to unblock...\n");
        return;
    }

    OMNITRACE_DEBUG("Unblocking signals [%s] on thread #%lu...\n",
                    get_signal_names(_signals).c_str(), threading::get_id());

    sigset_t _v = get_signal_set(_signals);
    thread_sigmask(SIG_UNBLOCK, &_v, nullptr);
}

void
post_process()
{
    OMNITRACE_SCOPED_THREAD_STATE(ThreadState::Internal);

    size_t _total_data       = 0;
    size_t _total_threads    = 0;
    auto   _external_samples = std::atomic<size_t>{ 0 };
    auto   _internal_samples = std::atomic<size_t>{ 0 };

    OMNITRACE_VERBOSE(2 || get_debug_sampling(), "Stopping sampling components...\n");
    omnitrace::component::backtrace::stop();
    for(size_t i = 0; i < max_supported_threads; ++i)
    {
        backtrace_metrics::configure(false, i);
        auto& _sampler = get_sampler(i);
        if(_sampler)
        {
            _sampler->set_offload(nullptr);
            _sampler->stop();
        }
    }

    auto _loaded_data = load_offload_buffer();
    for(size_t i = 0; i < max_supported_threads; ++i)
    {
        auto& _sampler = get_sampler(i);

        if(!_sampler)
        {
            // this should be relatively common
            OMNITRACE_CONDITIONAL_PRINT(
                get_debug() && get_verbose() >= 2,
                "Post-processing sampling entries for thread %lu skipped (no sampler)\n",
                i);
            continue;
        }

        auto* _init = get_sampler_init(i).get();

        if(!_init)
        {
            // this is not common
            OMNITRACE_PRINT("Post-processing sampling entries for thread %lu skipped "
                            "(not initialized)\n",
                            i);
            continue;
        }

        const auto& _thread_info = thread_info::get(i, SequentTID);

        OMNITRACE_VERBOSE(3 || get_debug_sampling(),
                          "Getting sampler data for thread %lu...\n", i);

        auto _raw_data = _sampler->get_data();
        for(auto litr : _loaded_data[i])
        {
            while(!litr.is_empty())
            {
                auto _v = sampler_bundle_t{};
                litr.read(&_v);
                _raw_data.emplace_back(std::move(_v));
            }
            litr.destroy();
        }

        OMNITRACE_VERBOSE(2 || get_debug_sampling(),
                          "Sampler data for thread %lu has %zu initial entries...\n", i,
                          _raw_data.size());

        OMNITRACE_CI_THROW(
            _sampler->get_sample_count() != _raw_data.size(),
            "Error! sampler recorded %zu samples but %zu samples were returned\n",
            _sampler->get_sample_count(), _raw_data.size());
        // single sample that is useless (backtrace to unblocking signals)
        if(_raw_data.size() == 1 && _raw_data.front().size() <= 1) _raw_data.clear();

        std::vector<sampling::bundle_t*> _data{};
        for(auto& itr : _raw_data)
        {
            auto* _bt = itr.get<backtrace>();
            auto* _ts = itr.get<backtrace_timestamp>();
            if(_thread_info && _bt && !_bt->empty() && _ts &&
               _thread_info->is_valid_time(_ts->get_timestamp()))
            {
                _data.emplace_back(&itr);
            }
        }

        _total_data += _data.size();
        _total_threads += (!_data.empty()) ? 1 : 0;

        if(!_data.empty())
        {
            OMNITRACE_VERBOSE(2 || get_debug_sampling(),
                              "Sampler data for thread %lu has %zu valid entries...\n", i,
                              _data.size());

            if(get_use_perfetto()) post_process_perfetto(i, _init, _data);
            if(get_use_timemory()) post_process_timemory(i, _init, _data);
        }
        else
        {
            OMNITRACE_VERBOSE(2 || get_debug_sampling(),
                              "Sampler data for thread %lu has zero valid entries out of "
                              "%zu... (skipped)\n",
                              i, _raw_data.size());
        }
    }

    OMNITRACE_VERBOSE(3 || get_debug_sampling(),
                      "Destroying samplers and allocators...\n");

    for(size_t i = 0; i < max_supported_threads; ++i)
        get_sampler(i).reset();

    for(auto& itr : get_sampler_allocators())
    {
        if(itr) itr.reset();
    }

    if(get_offload_file())
    {
        get_offload_file()->remove();
        get_offload_file().reset();
    }

    OMNITRACE_VERBOSE(1 || get_debug_sampling(),
                      "Collected %zu samples from %zu threads... %zu samples out of %zu "
                      "were taken while within instrumented routines\n",
                      _total_data, _total_threads, _internal_samples.load(),
                      (_internal_samples + _external_samples));
}

namespace
{
void
post_process_perfetto(int64_t _tid, const bundle_t* _init,
                      const std::vector<bundle_t*>& _data)
{
    auto _valid_metrics = backtrace_metrics::valid_array_t{};

    for(const auto& itr : _data)
    {
        const auto* _bt_mt = itr->get<backtrace_metrics>();
        if(_bt_mt) _valid_metrics |= _bt_mt->get_valid();
    }

    if(trait::runtime_enabled<backtrace_metrics>::get())
    {
        OMNITRACE_VERBOSE(3 || get_debug_sampling(),
                          "[%li] Post-processing metrics for perfetto...\n", _tid);
        backtrace_metrics::init_perfetto(_tid, _valid_metrics);
        for(const auto& itr : _data)
        {
            const auto* _bt_metrics = itr->get<backtrace_metrics>();
            const auto* _bt_time    = itr->get<backtrace_timestamp>();
            if(!_bt_metrics || !_bt_time) continue;
            if(_bt_time->get_tid() != _tid) continue;
            _bt_metrics->post_process_perfetto(_tid, _bt_time->get_timestamp());
        }
        backtrace_metrics::fini_perfetto(_tid, _valid_metrics);
    }

    OMNITRACE_VERBOSE(3 || get_debug_sampling(),
                      "[%li] Post-processing backtraces for perfetto...\n", _tid);

    const auto& _thread_info = thread_info::get(_tid, SequentTID);
    OMNITRACE_CI_THROW(!_thread_info, "No valid thread info for tid=%li\n", _tid);

    if(!_thread_info) return;

    uint64_t _beg_ns = _thread_info->get_start();
    uint64_t _end_ns = _thread_info->get_stop();
    uint64_t _last_ts =
        std::max<uint64_t>(_init->get<backtrace_timestamp>()->get_timestamp(), _beg_ns);

    auto _track = tracing::get_perfetto_track(
        category::sampling{},
        [](auto _seq_id, auto _sys_id) {
            return TIMEMORY_JOIN(" ", "Thread", _seq_id, "(S)", _sys_id);
        },
        _thread_info->index_data->sequent_value, _thread_info->index_data->system_value);

    tracing::push_perfetto_track(category::sampling{}, "samples [omnitrace]", _track,
                                 _beg_ns, [&](perfetto::EventContext ctx) {
                                     if(config::get_perfetto_annotations())
                                     {
                                         tracing::add_perfetto_annotation(ctx, "begin_ns",
                                                                          _beg_ns);
                                     }
                                 });

    auto _as_hex = [](auto _v) { return JOIN("", "0x", std::hex, _v); };

    auto _labels = backtrace_metrics::get_hw_counter_labels(_tid);
    for(const auto& itr : _data)
    {
        const auto* _bt_ts = itr->get<backtrace_timestamp>();
        const auto* _bt_cs = itr->get<backtrace>();
        const auto* _bt_mt = itr->get<backtrace_metrics>();

        if(!_bt_ts || !_bt_cs || !_bt_mt) continue;
        if(_bt_ts->get_tid() != _tid) continue;

        static std::set<std::string> _static_strings{};
        const auto*                  _last = _init;
        auto   _patched_data               = backtrace::filter_and_patch(_bt_cs->get());
        size_t _ncount                     = 0;
        for(const auto& iitr : _patched_data)
        {
            uint64_t _beg = _last_ts;
            uint64_t _end = _bt_ts->get_timestamp();
            if(!_thread_info->is_valid_lifetime({ _beg, _end })) continue;

            auto _ncur = _ncount++;
            // the begin/end + HW counters will be same for entire call-stack so only
            // annotate
            //  the top and the bottom functons to keep the data consumption low
            bool _include_common = (_ncur == 0 || _ncur + 1 == _patched_data.size());

            // Only annotate HW counters when:
            //  1. when we can compute a difference from the last sample
            //  2. when the number of HW counters b/t this sample and last are the same
            bool _include_hw =
                _include_common && (_last != nullptr) &&
                _bt_mt->get_hw_counters().size() ==
                    _last->get<backtrace_metrics>()->get_hw_counters().size();

            auto _hw_counters_enabled = [](const auto* _bt_v) {
                return (_bt_v != nullptr) &&
                       (*_bt_v)(type_list<backtrace_metrics::hw_counters>{}) &&
                       (*_bt_v)(category::thread_hardware_counter{});
            };

            // annotations common to both modes
            auto _common_annotate = [&](::perfetto::EventContext& ctx, bool _is_last) {
                if(_include_common && _is_last)
                {
                    tracing::add_perfetto_annotation(ctx, "begin_ns", _beg);
                    tracing::add_perfetto_annotation(ctx, "end_ns", _end);
                }
                if(_include_hw && _is_last && _last &&
                   _hw_counters_enabled(_last->get<backtrace_metrics>()) &&
                   _hw_counters_enabled(_bt_mt))
                {
                    // current values when read
                    auto _hw_cnt_vals = _bt_mt->get_hw_counters();
                    // compute difference from last sample to provide the HW counters for
                    // this sample
                    tim::math::minus(_hw_cnt_vals,
                                     _last->get<backtrace_metrics>()->get_hw_counters());
                    for(size_t i = 0; i < _labels.size(); ++i)
                        tracing::add_perfetto_annotation(ctx, _labels.at(i),
                                                         _hw_cnt_vals.at(i));
                }
            };

            if(get_sampling_include_inlines() && iitr.lineinfo)
            {
                auto _lines = iitr.lineinfo.lines;
                std::reverse(_lines.begin(), _lines.end());
                size_t _n = 0;
                for(const auto& litr : _lines)
                {
                    const auto* _name =
                        _static_strings.emplace(demangle(litr.name)).first->c_str();
                    auto _info = JOIN(':', litr.location, litr.line);
                    tracing::push_perfetto_track(
                        category::sampling{}, _name, _track, _beg,
                        [&](perfetto::EventContext ctx) {
                            if(config::get_perfetto_annotations())
                            {
                                _common_annotate(ctx, (_n == 0 && _ncur == 0) ||
                                                          (_n + 1 == _lines.size()));
                                tracing::add_perfetto_annotation(ctx, "file",
                                                                 iitr.location);
                                tracing::add_perfetto_annotation(ctx, "lineinfo", _info);
                                tracing::add_perfetto_annotation(ctx, "inlined",
                                                                 (_n++ > 0));
                            }
                        });
                    tracing::pop_perfetto_track(category::sampling{}, _name, _track,
                                                _end);
                }
            }
            else
            {
                const auto* _name = _static_strings.emplace(iitr.name).first->c_str();
                tracing::push_perfetto_track(
                    category::sampling{}, _name, _track, _beg,
                    [&](perfetto::EventContext ctx) {
                        if(config::get_perfetto_annotations())
                        {
                            _common_annotate(ctx, true);
                            tracing::add_perfetto_annotation(ctx, "file", iitr.location);
                            tracing::add_perfetto_annotation(ctx, "pc",
                                                             _as_hex(iitr.address));
                            tracing::add_perfetto_annotation(ctx, "line_address",
                                                             _as_hex(iitr.line_address));
                            if(iitr.lineinfo)
                            {
                                auto _lines = iitr.lineinfo.lines;
                                std::reverse(_lines.begin(), _lines.end());
                                size_t _n = 0;
                                for(const auto& litr : _lines)
                                {
                                    auto _label = JOIN('-', "lineinfo", _n++);
                                    tracing::add_perfetto_annotation(
                                        ctx, _label.c_str(),
                                        JOIN('@', demangle(litr.name),
                                             JOIN(':', litr.location, litr.line)));
                                }
                            }
                        }
                    });

                tracing::pop_perfetto_track(category::sampling{}, _name, _track, _end);
            }
        }
        _last_ts = _bt_ts->get_timestamp();
        _last    = itr;
    }

    tracing::pop_perfetto_track(category::sampling{}, "samples [omnitrace]", _track,
                                _end_ns, [&](perfetto::EventContext ctx) {
                                    if(config::get_perfetto_annotations())
                                    {
                                        tracing::add_perfetto_annotation(ctx, "end_ns",
                                                                         _end_ns);
                                    }
                                });
}

void
post_process_timemory(int64_t _tid, const bundle_t* _init,
                      const std::vector<bundle_t*>& _data)
{
    auto _depth_sum = std::map<int64_t, std::map<int64_t, int64_t>>{};

    OMNITRACE_VERBOSE(3 || get_debug_sampling(),
                      "[%li] Post-processing data for timemory...\n", _tid);

    const auto* _last = _init;
    for(const auto& itr : _data)
    {
        using bundle_t = tim::lightweight_tuple<comp::trip_count, sampling_wall_clock,
                                                sampling_cpu_clock, hw_counters>;

        auto*       _bt_data      = itr->get<backtrace>();
        auto*       _bt_time      = itr->get<backtrace_timestamp>();
        auto*       _bt_metrics   = itr->get<backtrace_metrics>();
        const auto* _last_metrics = _last->get<backtrace_metrics>();

        if(!_bt_data || !_bt_time) continue;

        double _elapsed_wc = (_bt_time->get_timestamp() -
                              _last->get<backtrace_timestamp>()->get_timestamp());

        std::vector<bundle_t> _tc{};
        _tc.reserve(_bt_data->size());

        // generate the instances of the tuple of components and start them
        for(const auto& iitr : backtrace::filter_and_patch(_bt_data->get()))
        {
            _tc.emplace_back(tim::string_view_t{ iitr.name });
            _tc.back().push(_bt_time->get_tid());
            _tc.back().start();
        }

        // stop the instances and update the values as needed
        for(size_t i = 0; i < _tc.size(); ++i)
        {
            auto&  iitr   = _tc.at(_tc.size() - i - 1);
            size_t _depth = 0;
            _depth_sum[_bt_time->get_tid()][_depth] += 1;
            iitr.stop();
            if constexpr(tim::trait::is_available<sampling_wall_clock>::value)
            {
                auto* _sc = iitr.get<sampling_wall_clock>();
                if(_sc)
                {
                    auto _value = _elapsed_wc / sampling_wall_clock::get_unit();
                    _sc->set_value(_value);
                    _sc->set_accum(_value);
                }
            }
            if constexpr(tim::trait::is_available<sampling_cpu_clock>::value)
            {
                auto* _cc = iitr.get<sampling_cpu_clock>();

                if(_cc && _bt_metrics && _last_metrics &&
                   (*_bt_metrics)(category::thread_cpu_time{}) &&
                   (*_last_metrics)(category::thread_cpu_time{}))
                {
                    double _elapsed_cc = (_bt_metrics->get_cpu_timestamp() -
                                          _last_metrics->get_cpu_timestamp());

                    _cc->set_value(_elapsed_cc / sampling_cpu_clock::get_unit());
                    _cc->set_accum(_elapsed_cc / sampling_cpu_clock::get_unit());
                }
            }
            if constexpr(tim::trait::is_available<hw_counters>::value)
            {
                auto _hw_counters_enabled = [](const auto* _bt_v) {
                    return (_bt_v != nullptr) &&
                           (*_bt_v)(type_list<backtrace_metrics::hw_counters>{}) &&
                           (*_bt_v)(category::thread_hardware_counter{});
                };

                if(_bt_metrics && _last_metrics && _hw_counters_enabled(_bt_metrics) &&
                   _hw_counters_enabled(_last_metrics))
                {
                    auto _hw_cnt_vals = _bt_metrics->get_hw_counters();
                    if(_bt_metrics->get_hw_counters().size() ==
                       _last_metrics->get_hw_counters().size())
                    {
                        for(size_t k = 0; k < _bt_metrics->get_hw_counters().size(); ++k)
                        {
                            if(_last_metrics->get_hw_counters()[k] > _hw_cnt_vals[k])
                                _hw_cnt_vals[k] -= _last_metrics->get_hw_counters()[k];
                        }
                    }
                    auto* _hw_counter = iitr.get<hw_counters>();
                    if(_hw_counter)
                    {
                        _hw_counter->set_value(_hw_cnt_vals);
                        _hw_counter->set_accum(_hw_cnt_vals);
                    }
                }
            }
            iitr.pop();
        }
        _last = itr;
    }

    for(auto&& itr : _data)
    {
        using bundle_t =
            tim::lightweight_tuple<sampling_percent, quirk::config<quirk::tree_scope>>;

        auto* _bt_data = itr->get<backtrace>();
        auto* _bt_time = itr->get<backtrace_timestamp>();

        if(!_bt_time || !_bt_data) continue;
        if(_depth_sum.find(_bt_time->get_tid()) == _depth_sum.end()) continue;

        std::vector<bundle_t> _tc{};
        _tc.reserve(_bt_data->size());

        // generate the instances of the tuple of components and start them
        for(const auto& iitr : backtrace::filter_and_patch(_bt_data->get()))
        {
            _tc.emplace_back(tim::string_view_t{ iitr.name });
            _tc.back().push(_bt_time->get_tid());
            _tc.back().start();
        }

        // stop the instances and update the values as needed
        for(size_t i = 0; i < _tc.size(); ++i)
        {
            auto&  iitr   = _tc.at(_tc.size() - i - 1);
            size_t _depth = 0;
            double _value = (1.0 / _depth_sum[_bt_time->get_tid()][_depth]) * 100.0;
            iitr.store(std::plus<double>{}, _value);
            iitr.stop();
            iitr.pop();
        }
    }
}

struct sampling_initialization
{
    static void preinit()
    {
        sampling_wall_clock::label()       = "sampling_wall_clock";
        sampling_wall_clock::description() = "Wall clock time (via sampling)";

        sampling_cpu_clock::label()       = "sampling_cpu_clock";
        sampling_cpu_clock::description() = "CPU clock time (via sampling)";

        sampling_percent::label()       = "sampling_percent";
        sampling_percent::description() = "Percentage of samples";

        sampling_gpu_busy::label()       = "sampling_gpu_busy_percent";
        sampling_gpu_busy::description() = "Utilization of GPU(s)";
        sampling_gpu_busy::set_precision(0);
        sampling_gpu_busy::set_format_flags(sampling_gpu_busy::get_format_flags() &
                                            std::ios_base::showpoint);

        sampling_gpu_memory::label()       = "sampling_gpu_memory_usage";
        sampling_gpu_memory::description() = "Memory usage of GPU(s)";

        sampling_gpu_power::label()        = "sampling_gpu_power";
        sampling_gpu_power::description()  = "Power usage of GPU(s)";
        sampling_gpu_power::unit()         = units::watt;
        sampling_gpu_power::display_unit() = "watts";
        sampling_gpu_power::set_precision(2);
        sampling_gpu_power::set_format_flags(sampling_gpu_power::get_format_flags());

        sampling_gpu_temp::label()        = "sampling_gpu_temperature";
        sampling_gpu_temp::description()  = "Temperature of GPU(s)";
        sampling_gpu_temp::unit()         = 1;
        sampling_gpu_temp::display_unit() = "degC";
        sampling_gpu_temp::set_precision(1);
        sampling_gpu_temp::set_format_flags(sampling_gpu_temp::get_format_flags());
    }
};
}  // namespace
}  // namespace sampling
}  // namespace omnitrace

TIMEMORY_INVOKE_PREINIT(omnitrace::sampling::sampling_initialization)