diff options
| -rw-r--r-- | apt-pkg/contrib/perf.h | 153 | ||||
| -rw-r--r-- | apt-pkg/depcache.cc | 2 | ||||
| -rw-r--r-- | apt-pkg/edsp.cc | 2 |
3 files changed, 157 insertions, 0 deletions
diff --git a/apt-pkg/contrib/perf.h b/apt-pkg/contrib/perf.h new file mode 100644 index 000000000..7a56d5149 --- /dev/null +++ b/apt-pkg/contrib/perf.h @@ -0,0 +1,153 @@ +/* + * Performance measurements + * + * Copyright (C) 2026 Julian Andres Klode <jak@debian.org> + * + * SPDX-License-Identifier: GPL-2.0+ + */ + +#ifndef APT_PERF_H +#define APT_PERF_H +#if defined(APT_COMPILING_APT) && defined(__linux__) +#include <apt-pkg/macros.h> + +#include <array> +#include <cstdint> +#include <cstdio> +#include <cstdlib> +#include <cstring> +#include <sstream> + +#include <fcntl.h> +#include <linux/perf_event.h> +#include <sys/file.h> +#include <sys/ioctl.h> +#include <sys/syscall.h> +#include <unistd.h> + +namespace APT +{ + +/** + * \brief A scoped object that will log the performance counters. + * + * Set the "APT_PERFORMANCE_LOG" environment variable to produce a + * JSONL file with records for various contexts, such as the solver. + */ +class PerformanceContext +{ + struct measurement + { + uint32_t type; + uint64_t config; + const char *name; + }; + + static constexpr std::array<measurement, 10> measurements{ + measurement{PERF_TYPE_HARDWARE, PERF_COUNT_HW_INSTRUCTIONS, "instructions"}, + measurement{PERF_TYPE_HARDWARE, PERF_COUNT_HW_CPU_CYCLES, "cpu_cycles"}, + measurement{PERF_TYPE_HARDWARE, PERF_COUNT_HW_REF_CPU_CYCLES, "ref_cpu_cycles"}, + measurement{PERF_TYPE_HARDWARE, PERF_COUNT_HW_CACHE_REFERENCES, "cache_references"}, + measurement{PERF_TYPE_HARDWARE, PERF_COUNT_HW_CACHE_MISSES, "cache_misses"}, + measurement{PERF_TYPE_HARDWARE, PERF_COUNT_HW_BRANCH_INSTRUCTIONS, "branch_instructions"}, + measurement{PERF_TYPE_HARDWARE, PERF_COUNT_HW_BRANCH_MISSES, "branch_misses"}, + measurement{PERF_TYPE_SOFTWARE, PERF_COUNT_SW_CPU_CLOCK, "cpu_clock"}, + measurement{PERF_TYPE_SOFTWARE, PERF_COUNT_SW_PAGE_FAULTS, "page_faults"}, + measurement{PERF_TYPE_SOFTWARE, PERF_COUNT_SW_CPU_MIGRATIONS, "cpu_migrations"}, + }; + + /// Output filename + std::string out; + /// Name of the context + std::string name; + /// FDs to communicate with the kernel + std::array<int, measurements.size()> fds; + + // Wrapper for the system call + static long perf_event_open(struct perf_event_attr *hw_event, pid_t pid, + int cpu, int group_fd, unsigned long flags) + { + return syscall(__NR_perf_event_open, hw_event, pid, cpu, group_fd, flags); + } + + // Wrapper for the system call + static int open_perf_counter(uint32_t type, uint64_t config) + { + struct perf_event_attr pe; + memset(&pe, 0, sizeof(struct perf_event_attr)); + pe.type = type; + pe.size = sizeof(struct perf_event_attr); + pe.config = config; + pe.disabled = 1; + pe.exclude_kernel = 1; + pe.exclude_hv = 1; + + int fd = perf_event_open(&pe, 0, -1, -1, 0); + return fd; + } + + public: + /// Construct a new scoped performance context + PerformanceContext(std::string name) : name(name) + { + if (auto out = getenv("APT_PERFORMANCE_LOG")) + this->out = out; + if (likely(out.empty())) + return; + for (size_t i = 0; i < measurements.size(); ++i) + fds[i] = open_perf_counter(measurements[i].type, measurements[i].config); + for (auto fd : fds) + must_succeed(fd == -1 || ioctl(fd, PERF_EVENT_IOC_RESET, 0) != -1); + for (auto fd : fds) + must_succeed(fd == -1 || ioctl(fd, PERF_EVENT_IOC_ENABLE, 0) != -1); + } + /// Collect the results and store them in the specified performance file + ~PerformanceContext() + { + if (likely(out.empty())) + return; + for (auto fd : fds) + must_succeed(fd == -1 || ioctl(fd, PERF_EVENT_IOC_DISABLE, 0) != -1); + + std::array<long long, measurements.size()> values; + for (size_t i = 0; i < measurements.size(); ++i) + must_succeed(fds[i] == -1 || read(fds[i], &values[i], sizeof(values[i])) == sizeof(values[i])); + for (auto fd : fds) + must_succeed(fd == -1 || close(fd) == 0); + + std::stringstream ss; + ss.imbue(std::locale::classic()); + ss << "{\"context\": " << '"' << name << '"'; + for (size_t i = 0; i < measurements.size(); ++i) + { + ss << ", "; + ss << '"' << measurements[i].name << '"' << ": " << values[i]; + } + + ss << "}\n"; + + std::string entry = ss.str(); + + // Atomically append a line to the JSONL file, allowing all users to read it + int fd = open(out.c_str(), O_WRONLY | O_CREAT | O_APPEND, 0666); + must_succeed(fd != -1); + must_succeed(flock(fd, LOCK_EX) == 0); + must_succeed(write(fd, entry.c_str(), entry.size()) == static_cast<ssize_t>(entry.size())); + must_succeed(flock(fd, LOCK_UN) == 0); + must_succeed(close(fd) == 0); + } +}; + +} // namespace APT + +#else +namespace APT +{ +struct PerformanceContext +{ + PerformanceContext(const char *) {}; + ~PerformanceContext() {}; +}; +} // namespace APT +#endif +#endif diff --git a/apt-pkg/depcache.cc b/apt-pkg/depcache.cc index f7f508f85..2a9ef50d2 100644 --- a/apt-pkg/depcache.cc +++ b/apt-pkg/depcache.cc @@ -19,6 +19,7 @@ #include <apt-pkg/error.h> #include <apt-pkg/fileutl.h> #include <apt-pkg/macros.h> +#include <apt-pkg/perf.h> #include <apt-pkg/pkgcache.h> #include <apt-pkg/prettyprinters.h> #include <apt-pkg/progress.h> @@ -225,6 +226,7 @@ bool pkgDepCache::CheckConsistency(char const *const msgtag) /*{{{*/ /* This allocats the extension buffers and initializes them. */ bool pkgDepCache::Init(OpProgress * const Prog) { + APT::PerformanceContext perf{"pkgDepCache::Init"}; // Suppress mark updates during this operation (just in case) and // run a mark operation when Init terminates. ActionGroup actions(*this); diff --git a/apt-pkg/edsp.cc b/apt-pkg/edsp.cc index 2d7fdcc3c..5a9808ff4 100644 --- a/apt-pkg/edsp.cc +++ b/apt-pkg/edsp.cc @@ -15,6 +15,7 @@ #include <apt-pkg/error.h> #include <apt-pkg/fileutl.h> #include <apt-pkg/packagemanager.h> +#include <apt-pkg/perf.h> #include <apt-pkg/pkgcache.h> #include <apt-pkg/pkgsystem.h> #include <apt-pkg/prettyprinters.h> @@ -796,6 +797,7 @@ bool EDSP::ResolveExternal(const char* const solver, pkgDepCache &Cache, unsigned int const flags, OpProgress *Progress) { if (strstr(solver, "3.") == solver) { + APT::PerformanceContext context{"APT::Solver"}; APT::Solver::DependencySolver s(Cache.GetCache(), Cache.GetPolicy(), (EDSP::Request::Flags)flags); FileFd output; bool res = true; |