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Improve run-time profiling

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The --prof-threads option has been split into two independent options:
1. --prof-exec, for collecting verilator_gantt and other execution
related profiling data, and
2. --prof-pgo, for collecting data needed for PGO

The implementation of execution profiling is extricated from
VlThreadPool and is now a separate class VlExecutionProfiler. This means
--prof-exec can now be used for single-threaded models (though it does
not measure a lot of things just yet). For consistency VerilatedProfiler
is renamed VlPgoProfiler. Both VlExecutionProfiler and VlPgoProfiler are
in verilated_profiler.{h/cpp}, but can be used completely independently.

Also re-worked the execution profile format so it now only emits events
without holding onto any temporaries. This is in preparation for some
future optimizations that would be hindered by the introduction of function
locals via AstText.

Also removed the Barrier event. Clearing the profile buffers is not
notably more expensive as the profiling records are trivially
destructible.
This commit is contained in:
Geza Lore
2022-03-27 15:57:30 +02:00
parent c7440b250f
commit b1b5b5dfe2
40 changed files with 900 additions and 712 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/V3EmitCSyms.cpp
+17 -20
View File
@@ -395,7 +395,7 @@ void EmitCSyms::emitSymHdr() {
if (v3Global.needTraceDumper()) {
puts("#include \"" + v3Global.opt.traceSourceLang() + ".h\"\n");
}
if (v3Global.opt.profThreads()) puts("#include \"verilated_profiler.h\"\n");
if (v3Global.opt.usesProfiler()) puts("#include \"verilated_profiler.h\"\n");
puts("\n// INCLUDE MODEL CLASS\n");
puts("\n#include \"" + topClassName() + ".h\"\n");
@@ -445,18 +445,15 @@ void EmitCSyms::emitSymHdr() {
}
puts("bool __Vm_didInit = false;\n");
if (v3Global.opt.profExec()) {
puts("\n// EXECUTION PROFILING\n");
puts("VlExecutionProfiler __Vm_executionProfiler;\n");
}
if (v3Global.opt.mtasks()) {
puts("\n// MULTI-THREADING\n");
puts("VlThreadPool* const __Vm_threadPoolp;\n");
puts("bool __Vm_even_cycle = false;\n");
if (v3Global.opt.profThreads()) {
// rdtsc() at current cycle start
puts("vluint64_t __Vm_profile_cycle_start = 0;\n");
// Time we finished analysis
puts("vluint64_t __Vm_profile_time_finished = 0;\n");
// Track our position in the cache warmup and actual profile window
puts("vluint32_t __Vm_profile_window_ct = 0;\n");
}
}
puts("\n// MODULE INSTANCE STATE\n");
@@ -477,8 +474,8 @@ void EmitCSyms::emitSymHdr() {
puts("];\n");
}
if (v3Global.opt.profThreads()) {
puts("\n// PROFILING\n");
if (v3Global.opt.profPgo()) {
puts("\n// PGO PROFILING\n");
vluint64_t maxProfilerId = 0;
if (v3Global.opt.mtasks()) {
for (const V3GraphVertex* vxp
@@ -490,7 +487,7 @@ void EmitCSyms::emitSymHdr() {
}
}
++maxProfilerId; // As size must include 0
puts("VerilatedProfiler<" + cvtToStr(maxProfilerId) + "> _vm_profiler;\n");
puts("VlPgoProfiler<" + cvtToStr(maxProfilerId) + "> _vm_pgoProfiler;\n");
}
if (!m_scopeNames.empty()) { // Scope names
@@ -682,8 +679,8 @@ void EmitCSyms::emitSymImp() {
puts("if (__Vm_dumping) _traceDumpClose();\n");
puts("#endif // VM_TRACE\n");
}
if (v3Global.opt.profThreads()) {
puts("_vm_profiler.write(\"" + topClassName()
if (v3Global.opt.profPgo()) {
puts("_vm_pgoProfiler.write(\"" + topClassName()
+ "\", _vm_contextp__->profVltFilename());\n");
}
if (v3Global.opt.mtasks()) puts("delete __Vm_threadPoolp;\n");
@@ -719,8 +716,8 @@ void EmitCSyms::emitSymImp() {
// that calls eval() becomes the final Nth thread for the
// duration of the eval call.
puts(" , __Vm_threadPoolp{new VlThreadPool{_vm_contextp__, "
+ cvtToStr(v3Global.opt.threads() - 1) + ", " + cvtToStr(v3Global.opt.profThreads())
+ "}}\n");
+ cvtToStr(v3Global.opt.threads() - 1) + ", "
+ (v3Global.opt.profExec() ? "&__Vm_executionProfiler" : "nullptr") + "}}\n");
}
puts(" // Setup module instances\n");
@@ -741,14 +738,14 @@ void EmitCSyms::emitSymImp() {
}
puts("{\n");
if (v3Global.opt.profThreads()) {
puts("// Configure profiling\n");
if (v3Global.opt.profPgo()) {
puts("// Configure profiling for PGO\n");
if (v3Global.opt.mtasks()) {
for (const V3GraphVertex* vxp
= v3Global.rootp()->execGraphp()->depGraphp()->verticesBeginp();
vxp; vxp = vxp->verticesNextp()) {
ExecMTask* const mtp = dynamic_cast<ExecMTask*>(const_cast<V3GraphVertex*>(vxp));
puts("_vm_profiler.addCounter(" + cvtToStr(mtp->profilerId()) + ", \""
puts("_vm_pgoProfiler.addCounter(" + cvtToStr(mtp->profilerId()) + ", \""
+ mtp->hashName() + "\");\n");
}
}