rocm-systems/projects/rocprofiler/plugin/ctf/barectf_tracer.h

/* Copyright (c) 2022 Advanced Micro Devices, Inc.

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 of this software and associated documentation files (the "Software"), to deal
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 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.

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 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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#ifndef PLUGIN_CTF_BARECTF_TRACER_H
#define PLUGIN_CTF_BARECTF_TRACER_H

#include <cstdlib>
#include <memory>
#include <vector>
#include <string>
#include "src/utils/filesystem.hpp"

#include "barectf_event_record.h"
#include "barectf_writer.h"

namespace rocm_ctf {

// A barectf tracer offers the AddEventRecord() method to add an event
// record which it will ultimately write to some CTF data stream file
// within some specified CTF trace directory.
//
// One important feature of such a tracer is that you don't need to add
// event records in order of time. A barectf tracer manages one or more
// barectf writers, each one managing a single barectf platform/context
// (CTF data stream file).
//
// All the CTF data stream files which a barectf tracer indirectly
// manages share a common specified prefix. You must not use the same
// prefix for two barectf tracers writing to the same CTF trace
// directory.
//
// `PlatformDescrT` is the specific barectf platform descriptor (see the
// documentation of the `BarectfPlatform` class template).
template <typename PlatformDescrT> class BarectfTracer final {
 public:
  // Specific barectf event record type.
  using EventRecord = typename BarectfWriter<PlatformDescrT>::EventRecord;

  // Builds a barectf tracer to write CTF packets of size `packet_size`
  // bytes to CTF data stream files having the prefix
  // `data_stream_file_name_prefix` within the CTF trace directory
  // `trace_dir`.
  //
  // The internal barectf writers manage event record queues having a
  // maximum size of `max_writer_queue_size`. Increasing
  // `max_writer_queue_size` increases the memory footprint of the
  // tracer, but may reduce the number of required CTF data stream files
  // to ensure time-ordered event records.
  explicit BarectfTracer(const std::size_t packet_size,
                         rocprofiler::common::filesystem::path trace_dir,
                         const char* const data_stream_file_name_prefix,
                         const std::size_t max_writer_queue_size = 200)
      : packet_size_{packet_size},
        trace_dir_{std::move(trace_dir)},
        data_stream_file_name_prefix_{data_stream_file_name_prefix},
        max_writer_queue_size_{max_writer_queue_size} {}

  // Disabled copy operations to make this class simpler.
  BarectfTracer(const BarectfTracer&) = delete;
  BarectfTracer& operator=(const BarectfTracer&) = delete;

  // Adds the event record `event_record` to this tracer.
  //
  // The clock value of `event_record` may be less than the clock value
  // of previously added event records.
  void AddEventRecord(typename EventRecord::SP event_record) {
    // Try to find a barectf writer to accept `event_record`.
    for (auto& writer : writers_) {
      if (writer->MayAddEventRecord(*event_record)) {
        // Found: add the event record to this writer and return.
        writer->AddEventRecord(std::move(event_record));
        return;
      }
    }

    // No barectf writer found: create a new one.
    std::ostringstream ss;

    ss << data_stream_file_name_prefix_ << writers_.size();
    writers_.emplace_back(new BarectfWriter<PlatformDescrT>{packet_size_, trace_dir_ / ss.str(),
                                                            max_writer_queue_size_});

    // Add the event record to this new barectf writer.
    assert(writers_.back()->MayAddEventRecord(*event_record));
    writers_.back()->AddEventRecord(std::move(event_record));
  }

 private:
  // CTF packet size.
  std::size_t packet_size_;

  // CTF trace directory.
  rocprofiler::common::filesystem::path trace_dir_;

  // CTF data stream file name prefix.
  std::string data_stream_file_name_prefix_;

  // Maximum event record queue size of a barectf writer.
  std::size_t max_writer_queue_size_;

  // barectf writers.
  std::vector<std::unique_ptr<BarectfWriter<PlatformDescrT>>> writers_;
};

}  // namespace rocm_ctf

#endif  // PLUGIN_CTF_BARECTF_TRACER_H