From 7c343eaaa75b4dbb28bcde31a4fddc9d8dcad50b Mon Sep 17 00:00:00 2001
From: Rosen Matev <rosen.matev@cern.ch>
Date: Fri, 6 Jan 2023 23:03:49 +0100
Subject: [PATCH] Add algorithm to programmatically enable/disable perf
---
GaudiProfiling/CMakeLists.txt | 12 +++
.../src/component/perf/PerfProfile.cpp | 78 +++++++++++++++++++
.../tests/pytest/test_perf_profile.py | 51 ++++++++++++
3 files changed, 141 insertions(+)
create mode 100644 GaudiProfiling/src/component/perf/PerfProfile.cpp
create mode 100644 GaudiProfiling/tests/pytest/test_perf_profile.py
diff --git a/GaudiProfiling/CMakeLists.txt b/GaudiProfiling/CMakeLists.txt
index a3da42da5e..8f39c939d4 100644
--- a/GaudiProfiling/CMakeLists.txt
+++ b/GaudiProfiling/CMakeLists.txt
@@ -111,6 +111,16 @@ gaudi_add_module(GaudiJemalloc
LINK GaudiKernel
GaudiAlgLib)
+#-----------------------------------
+# Linux perf
+#-----------------------------------
+# TODO: The PerfProfile algorithm should only be compiled for Linux
+# (and consequently the test should only run if PerfProfile is there).
+gaudi_add_module(GaudiPerf
+ SOURCES src/component/perf/PerfProfile.cpp
+ LINK GaudiKernel
+ GaudiAlgLib)
+
# Special handling of unresolved symbols in Jemmalloc.
# The profilers need to have libjemalloc.so pre-loaded to
# work, so it's better if the symbols stay undefined in case somebody tries to
@@ -122,6 +132,8 @@ if(GAUDI_USE_JEMALLOC)
COMMAND run ${CMAKE_COMMAND} -E env LD_PRELOAD=$<TARGET_PROPERTY:jemalloc::jemalloc,LOCATION> gaudirun.py)
endif()
+gaudi_add_tests(pytest)
+
# Install python modules
gaudi_install(PYTHON)
# Install other scripts
diff --git a/GaudiProfiling/src/component/perf/PerfProfile.cpp b/GaudiProfiling/src/component/perf/PerfProfile.cpp
new file mode 100644
index 0000000000..a3914e49e9
--- /dev/null
+++ b/GaudiProfiling/src/component/perf/PerfProfile.cpp
@@ -0,0 +1,78 @@
+/***********************************************************************************\
+* (c) Copyright 1998-2023 CERN for the benefit of the LHCb and ATLAS collaborations *
+* *
+* This software is distributed under the terms of the Apache version 2 licence, *
+* copied verbatim in the file "LICENSE". *
+* *
+* In applying this licence, CERN does not waive the privileges and immunities *
+* granted to it by virtue of its status as an Intergovernmental Organization *
+* or submit itself to any jurisdiction. *
+\***********************************************************************************/
+#include "GaudiAlg/Consumer.h"
+#include <fcntl.h>
+#include <string_view>
+#include <sys/stat.h>
+
+/** Algorithm to enable/disable profiling with Linux perf at given events.
+ *
+ * Needs at least perf 5.9. To control perf record, start it as
+ *
+ * perf record -D -1 --control fifo:GaudiPerfProfile.fifo ... gaudirun.py ...
+ *
+ * The path to the control fifo (GaudiPerfProfile.fifo) is configurable
+ * with the FIFOPath property. The fifo must be created before running perf.
+ *
+ */
+struct PerfProfile final : Gaudi::Functional::Consumer<void()> {
+ using Consumer::Consumer;
+
+ StatusCode initialize() override {
+ return Consumer::initialize().andThen( [this]() {
+ m_fifo = ::open( m_fifoPath.value().c_str(), O_WRONLY | O_NONBLOCK );
+ if ( m_fifo == -1 ) {
+ fatal() << "open(\"" << m_fifoPath.value() << "\"): " << ::strerror( errno ) << endmsg;
+ return StatusCode::FAILURE;
+ }
+ return StatusCode::SUCCESS;
+ } );
+ }
+
+ StatusCode finalize() override {
+ if ( m_fifo != -1 ) { ::close( m_fifo ); }
+ return Consumer::finalize();
+ }
+
+ void operator()() const override {
+ // We could use EventContext::evt(), however it is not always valid, as is the case with EvtSel="NONE". Instead, use
+ // an atomic counter.
+ auto eventNumber = m_eventNumber++;
+ if ( eventNumber == m_nStartFromEvent.value() ) {
+ warning() << "Starting perf profile at event " << eventNumber << endmsg;
+ fifo_write( "enable\n" );
+ }
+
+ if ( m_nStopAtEvent > 0 && eventNumber == m_nStopAtEvent.value() ) {
+ warning() << "Stopping perf profile at event " << eventNumber << endmsg;
+ fifo_write( "disable\n" );
+ }
+ }
+
+private:
+ void fifo_write( std::string_view s ) const {
+ if ( ::write( m_fifo, s.data(), s.size() ) < ssize_t( s.size() ) ) {
+ error() << "Write of \"" << s << "\" to FIFO failed: " << ::strerror( errno ) << endmsg;
+ }
+ }
+
+ mutable std::atomic<long unsigned> m_eventNumber = 0;
+ int m_fifo = -1;
+
+ Gaudi::Property<std::string> m_fifoPath{ this, "FIFOPath", "GaudiPerfProfile.fifo", "Path to perf control FIFO." };
+ Gaudi::Property<unsigned long> m_nStartFromEvent{ this, "StartFromEventN", 1,
+ "After what event we start profiling." };
+ Gaudi::Property<unsigned long> m_nStopAtEvent{
+ this, "StopAtEventN", 0,
+ "After what event we stop profiling. If 0 than we also profile finalization stage. Default = 0." };
+};
+
+DECLARE_COMPONENT( PerfProfile )
diff --git a/GaudiProfiling/tests/pytest/test_perf_profile.py b/GaudiProfiling/tests/pytest/test_perf_profile.py
new file mode 100644
index 0000000000..ae7b5b2827
--- /dev/null
+++ b/GaudiProfiling/tests/pytest/test_perf_profile.py
@@ -0,0 +1,51 @@
+#####################################################################################
+# (c) Copyright 2022-2023 CERN for the benefit of the LHCb and ATLAS collaborations #
+# #
+# This software is distributed under the terms of the Apache version 2 licence, #
+# copied verbatim in the file "LICENSE". #
+# #
+# In applying this licence, CERN does not waive the privileges and immunities #
+# granted to it by virtue of its status as an Intergovernmental Organization #
+# or submit itself to any jurisdiction. #
+#####################################################################################
+import os
+from threading import Thread
+
+from GaudiTests import run_gaudi
+
+
+def config():
+ from Configurables import ApplicationMgr, PerfProfile
+
+ prof = PerfProfile(
+ FIFOPath="control.fifo",
+ StartFromEventN=3,
+ StopAtEventN=8,
+ )
+ ApplicationMgr(
+ EvtSel="NONE",
+ EvtMax=10,
+ TopAlg=[prof],
+ )
+
+
+def test(tmp_path):
+ """Emulate perf record --control"""
+ fifo = tmp_path / "control.fifo"
+ fifo_lines = []
+ os.mkfifo(fifo)
+
+ def reader():
+ # open blocks until FIFO is opened for writing by PerfProfile::initialize(), so run it in a thread
+ with open(fifo) as f:
+ for line in f:
+ fifo_lines.append(line)
+
+ t = Thread(target=reader)
+ t.start()
+
+ run_gaudi(f"{__file__}:config", check=True, cwd=tmp_path)
+
+ t.join()
+
+ assert fifo_lines == ["enable\n", "disable\n"]
--
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