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2.8.3-1

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Optimization for Tree allreduce on A100.
Improve aggregation performance.
Use shared buffers for inter-node send/recv.
Add NVTX profiling hooks.
Accelerate alltoall connections by merging communication for all
channels.
Add support for one hop communication through NVLink, for faster
send/recv communication on cubemesh topologies like DGX-1.
Improve alltoall scheduling to better balance intra/inter node
communication.
Increase send/recv parallelism by 8x, each warp sending or
receiving to a different peer.
Net: move to v4.
Net: make flush operation asynchronous to accelerate alltoall.
Net: define maximum number of requests.
Fix hang when using LL128 protocol after 2^31 steps.
Fix #379 : topology injection failing when using less GPUs than
described in the XML.
Fix #394 : protocol mismatch causing hangs or crashes when using
one GPU per node.


[ROCm/rccl commit: 920dbe5b35]
Este commit está contenido en:
Sylvain Jeaugey
2020-09-04 14:35:05 -07:00
padre 0277094dd2
commit a8908b34ee
Se han modificado 90 ficheros con 11172 adiciones y 3209 borrados
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projects/rccl/src/graph/search.cc
+43 -17
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@@ -22,8 +22,18 @@ static float getMaxWidth(struct ncclTopoSystem* system, struct ncclTopoNode* gpu
}
return maxWidth;
}
static float getTotalWidth(struct ncclTopoSystem* system, struct ncclTopoNode* gpu) {
float nvlinkWidth = 0.0, pciWidth = 0.0;
for (int l=0; l<gpu->nlinks; l++) {
struct ncclTopoLink* link = gpu->links+l;
if (link->type == LINK_NVL) nvlinkWidth += link->width;
if (link->type == LINK_PCI) pciWidth = link->width;
}
return std::max(pciWidth, nvlinkWidth);
}
ncclResult_t ncclTopoSearchInit(struct ncclTopoSystem* system) {
system->maxWidth = 0.0;
system->totalWidth = 0.0;
int inter = system->nodes[NET].count;
if (inter == 0 && system->nodes[GPU].count == 1) {
system->maxWidth = LOC_WIDTH;
@@ -32,6 +42,7 @@ ncclResult_t ncclTopoSearchInit(struct ncclTopoSystem* system) {
for (int g=0; g<system->nodes[GPU].count; g++) {
struct ncclTopoNode* gpu = system->nodes[GPU].nodes+g;
system->maxWidth = std::max(system->maxWidth, getMaxWidth(system, gpu, inter ? NET : GPU));
system->totalWidth = std::max(system->totalWidth, getTotalWidth(system, gpu));
}
return ncclSuccess;
}
@@ -290,7 +301,7 @@ ncclResult_t ncclTopoCompareGraphs(struct ncclTopoGraph* graph, struct ncclTopoG
return ncclSuccess;
}
// 3. Less hops (but not at the price of going cross NICs)
if (graph->crossNic == refGraph->crossNic && graph->nHops < refGraph->nHops) *copy = 1;
if (graph->pattern == refGraph->pattern && graph->crossNic == refGraph->crossNic && graph->nHops < refGraph->nHops) *copy = 1;
return ncclSuccess;
}
@@ -326,11 +337,26 @@ ncclResult_t ncclTopoSearchRecGpu(struct ncclTopoSystem* system, struct ncclTopo
struct ncclTopoNode* net = system->nodes[NET].nodes+n;
if (graph->pattern == NCCL_TOPO_PATTERN_TREE && net->id != startNet->id) continue; // Trees are symmetric
if (graph->crossNic != 1 && (net->net.asic != startNet->net.asic || net->net.port != startNet->net.port)) continue;
// Balanced Tree : count half of the bandwidth on first two GPUs
int nextBackToNet = -1;
float speedInterSave = graph->speedInter;
if (graph->pattern == NCCL_TOPO_PATTERN_BALANCED_TREE) {
// Count half of the bandwidth on each of the first two GPUs
if (step == 0) nextBackToNet = 1;
else if (net->id != graph->inter[graph->nChannels*2+1]) continue;
graph->speedInter /= 2;
}
NCCLCHECK(ncclTopoFollowPath(system, graph, GPU, g, NET, n, 1, &net));
graph->speedInter = speedInterSave;
if (net) {
graph->inter[graph->nChannels*2+1] = net->id;
NCCLCHECK(ncclTopoSearchRecGpu(system, graph, saveGraph, gpu, step, -1, backToFirstRank, forcedOrder, time));
NCCLCHECK(ncclTopoSearchRecGpu(system, graph, saveGraph, gpu, step, nextBackToNet, backToFirstRank, forcedOrder, time));
if (graph->pattern == NCCL_TOPO_PATTERN_BALANCED_TREE) graph->speedInter /= 2;
NCCLCHECK(ncclTopoFollowPath(system, graph, GPU, g, NET, n, -1, &net));
graph->speedInter = speedInterSave;
}
}
}
@@ -460,13 +486,12 @@ ncclResult_t ncclTopoSearchRecNet(struct ncclTopoSystem* system, struct ncclTopo
ncclResult_t ncclTopoSearchParams(struct ncclTopoSystem* system, int pattern, int* backToNet, int* backToFirstRank) {
if (system->nodes[NET].count) {
if (pattern == NCCL_TOPO_PATTERN_RING) *backToNet = system->nodes[GPU].count-1;
else if (pattern == NCCL_TOPO_PATTERN_TREE) *backToNet = 0;
else *backToNet = 1;
if (pattern == NCCL_TOPO_PATTERN_SPLIT_TREE_LOOP) *backToFirstRank = system->nodes[GPU].count-1;
else *backToFirstRank = -1;
else if (pattern == NCCL_TOPO_PATTERN_SPLIT_TREE) *backToNet = 1;
else *backToNet = 0;
*backToFirstRank = -1;
} else {
*backToNet = -1;
if (pattern == NCCL_TOPO_PATTERN_RING || pattern == NCCL_TOPO_PATTERN_SPLIT_TREE_LOOP) *backToFirstRank = system->nodes[GPU].count-1;
if (pattern == NCCL_TOPO_PATTERN_RING) *backToFirstRank = system->nodes[GPU].count-1;
else *backToFirstRank = -1;
}
return ncclSuccess;
@@ -503,7 +528,7 @@ ncclResult_t ncclTopoSearchRec(struct ncclTopoSystem* system, struct ncclTopoGra
/* User defined graph from XML file */
/************************************/
struct kvDict kvDictLinkType[] = { { "SYS", PATH_SYS }, { "PHB", PATH_PHB }, { "PIX", PATH_PIX }, { "PXB", PATH_PXB }, { "NVL", PATH_NVL }, { "LOC", PATH_LOC }, { NULL, 0 } };
struct kvDict kvDictLinkType[] = { { "SYS", PATH_SYS }, { "PHB", PATH_PHB }, { "PIX", PATH_PIX }, { "PXB", PATH_PXB }, { "NVL", PATH_NVL }, { "NVB", PATH_NVB}, { "LOC", PATH_LOC }, { NULL, 0 } };
ncclResult_t ncclTopoGetChannelFromXml(struct ncclXmlNode *xmlChannel, int c, struct ncclTopoSystem* system, struct ncclTopoGraph* graph) {
int ngpus = system->nodes[GPU].count;
int* inter = graph->inter+2*c;
@@ -623,7 +648,7 @@ ncclResult_t ncclTopoGetXmlFromGraphs(int ngraphs, struct ncclTopoGraph** graphs
return ncclSuccess;
}
float speedArray[] = { 42.0, 24.0, 21.0, 18.0, 15.0, 12.0, 10.0, 9.0, 7.0, 6.0, 5.0, 4.0, 3.0, 2.4, 1.2, 0.24, 0.12 };
float speedArray[] = { 42.0, 30.0, 24.0, 21.0, 18.0, 15.0, 12.0, 10.0, 9.0, 7.0, 6.0, 5.0, 4.0, 3.0, 2.4, 1.2, 0.24, 0.12 };
#define NSPEEDS (sizeof(speedArray)/sizeof(float))
ncclResult_t ncclTopoCompute(ncclTopoSystem* system, struct ncclTopoGraph* graph) {
@@ -651,11 +676,15 @@ ncclResult_t ncclTopoCompute(ncclTopoSystem* system, struct ncclTopoGraph* graph
if (ngpus == 1) if (graph->pattern != NCCL_TOPO_PATTERN_RING) graph->pattern = NCCL_TOPO_PATTERN_TREE;
// SPLIT_TREE works better on older archs.
int ccMin;
NCCLCHECK(ncclTopoGetCompCap(system, &ccMin, NULL));
if (ccMin < 80 && graph->pattern == NCCL_TOPO_PATTERN_BALANCED_TREE) graph->pattern = NCCL_TOPO_PATTERN_SPLIT_TREE;
struct ncclTopoGraph tmpGraph;
memcpy(&tmpGraph, graph, sizeof(struct ncclTopoGraph));
// First try crossnic, then decrease speed and finally increase speedIntra.
tmpGraph.pattern = graph->pattern;
int pass = 1;
int speedIndex = 0;
while (speedArray[speedIndex] > system->maxWidth && speedIndex < NSPEEDS-1) speedIndex++;
@@ -670,7 +699,7 @@ search:
NCCLCHECK(ncclTopoSearchRec(system, &tmpGraph, graph, &time));
#if 0
printf("Pattern %d, crossNic %d, Speed %g/%g, type %d/%d, channels %d-%d sameChannels %d -> nChannels %dx%g/%g %s\n", tmpGraph.pattern, tmpGraph.crossNic, tmpGraph.speedInter, tmpGraph.speedIntra, tmpGraph.typeInter, tmpGraph.typeIntra, tmpGraph.minChannels, tmpGraph.maxChannels, tmpGraph.sameChannels, graph->nChannels, graph->speedInter, graph->speedIntra, time == 0 ? "TIMEOUT" : "");
printf("Pattern %d, crossNic %d, Speed %g/%g, type %d/%d, channels %d-%d sameChannels %d -> nChannels %dx%g/%g %s\n", tmpGraph.pattern, tmpGraph.crossNic, tmpGraph.speedInter, tmpGraph.speedIntra, tmpGraph.typeInter, tmpGraph.typeIntra, tmpGraph.minChannels, tmpGraph.maxChannels, tmpGraph.sameChannels, graph->nChannels, graph->speedInter, graph->speedIntra, time == 0 ? "TIMEOUT" : time == -1 ? "PERFECT" : "");
for (int c=0; c<graph->nChannels; c++) {
printf("%2d : ", c);
for (int g=0; g<ngpus; g++) {
@@ -680,7 +709,8 @@ search:
}
#endif
// Optimal solution, stop here
if (graph->nChannels == graph->maxChannels && graph->speedInter == system->maxWidth) goto done;
if (time == -1) goto done;
if (graph->nChannels*graph->speedInter >= system->totalWidth) goto done;
if (pass == 1) {
// First pass, we don't have a solution yet ; try other options
@@ -694,7 +724,7 @@ search:
if (time != -1) globalTimeout += time;
else globalTimeout = NCCL_SEARCH_GLOBAL_TIMEOUT;
if (globalTimeout < 0) goto done;
if (globalTimeout < 0 && graph->nChannels) goto done;
int maxTypeIntra = system->nodes[NET].count > 0 ? tmpGraph.typeInter : PATH_SYS;
if (tmpGraph.typeIntra < maxTypeIntra && (graph->nChannels == 0 || tmpGraph.typeIntra < graph->typeIntra)) {
@@ -709,10 +739,6 @@ search:
tmpGraph.typeInter = PATH_PIX;
// Try a simpler tree
if (tmpGraph.pattern == NCCL_TOPO_PATTERN_SPLIT_TREE_LOOP) {
tmpGraph.pattern = NCCL_TOPO_PATTERN_SPLIT_TREE;
goto search;
}
if (tmpGraph.pattern == NCCL_TOPO_PATTERN_SPLIT_TREE) {
tmpGraph.pattern = NCCL_TOPO_PATTERN_TREE;
goto search;