From fa68eb367e79297bb1c0451cd92ad18a06edce96 Mon Sep 17 00:00:00 2001 From: Eelco Dolstra Date: Fri, 18 Nov 2022 13:40:59 +0100 Subject: [PATCH] Get CPU stats from the cgroup --- src/libstore/build-result.hh | 5 ++- src/libstore/build/derivation-goal.cc | 8 +++++ src/libstore/build/local-derivation-goal.cc | 14 +++++--- src/libstore/build/local-derivation-goal.hh | 2 +- src/libstore/cgroup.cc | 39 +++++++++++++++++++-- src/libstore/cgroup.hh | 14 +++++++- 6 files changed, 71 insertions(+), 11 deletions(-) diff --git a/src/libstore/build-result.hh b/src/libstore/build-result.hh index 24fb1f763..a5749cf33 100644 --- a/src/libstore/build-result.hh +++ b/src/libstore/build-result.hh @@ -5,7 +5,7 @@ #include #include - +#include namespace nix { @@ -78,6 +78,9 @@ struct BuildResult was repeated). */ time_t startTime = 0, stopTime = 0; + /* User and system CPU time the build took. */ + std::optional cpuUser, cpuSystem; + bool success() { return status == Built || status == Substituted || status == AlreadyValid || status == ResolvesToAlreadyValid; diff --git a/src/libstore/build/derivation-goal.cc b/src/libstore/build/derivation-goal.cc index 41d2e2a1c..9bc3dc742 100644 --- a/src/libstore/build/derivation-goal.cc +++ b/src/libstore/build/derivation-goal.cc @@ -869,6 +869,14 @@ void DerivationGoal::buildDone() cleanupPostChildKill(); + if (buildResult.cpuUser && buildResult.cpuSystem) { + debug("builder for '%s' terminated with status %d, user CPU %.3fs, system CPU %.3fs", + worker.store.printStorePath(drvPath), + status, + ((double) buildResult.cpuUser->count()) / 1000000, + ((double) buildResult.cpuSystem->count()) / 1000000); + } + bool diskFull = false; try { diff --git a/src/libstore/build/local-derivation-goal.cc b/src/libstore/build/local-derivation-goal.cc index 2d1e093ca..f273ebe8a 100644 --- a/src/libstore/build/local-derivation-goal.cc +++ b/src/libstore/build/local-derivation-goal.cc @@ -137,7 +137,7 @@ void LocalDerivationGoal::killChild() also send a conventional kill to the child. */ ::kill(-pid, SIGKILL); /* ignore the result */ - killSandbox(); + killSandbox(true); pid.wait(); } @@ -146,10 +146,14 @@ void LocalDerivationGoal::killChild() } -void LocalDerivationGoal::killSandbox() +void LocalDerivationGoal::killSandbox(bool getStats) { if (cgroup) { - destroyCgroup(*cgroup); + auto stats = destroyCgroup(*cgroup); + if (getStats) { + buildResult.cpuUser = stats.cpuUser; + buildResult.cpuSystem = stats.cpuSystem; + } } else if (buildUser) { @@ -270,7 +274,7 @@ void LocalDerivationGoal::cleanupPostChildKill() malicious user from leaving behind a process that keeps files open and modifies them after they have been chown'ed to root. */ - killSandbox(); + killSandbox(true); /* Terminate the recursive Nix daemon. */ stopDaemon(); @@ -410,7 +414,7 @@ void LocalDerivationGoal::startBuilder() /* Make sure that no other processes are executing under the sandbox uids. This must be done before any chownToBuilder() calls. */ - killSandbox(); + killSandbox(false); /* Right platform? */ if (!parsedDrv->canBuildLocally(worker.store)) diff --git a/src/libstore/build/local-derivation-goal.hh b/src/libstore/build/local-derivation-goal.hh index 1ec6b3649..34c4e9187 100644 --- a/src/libstore/build/local-derivation-goal.hh +++ b/src/libstore/build/local-derivation-goal.hh @@ -202,7 +202,7 @@ struct LocalDerivationGoal : public DerivationGoal /* Kill any processes running under the build user UID or in the cgroup of the build. */ - void killSandbox(); + void killSandbox(bool getStats); /* Create alternative path calculated from but distinct from the input, so we can avoid overwriting outputs (or other store paths) diff --git a/src/libstore/cgroup.cc b/src/libstore/cgroup.cc index 56e980be3..2a485f0f9 100644 --- a/src/libstore/cgroup.cc +++ b/src/libstore/cgroup.cc @@ -31,13 +31,16 @@ std::map getCgroups(const Path & cgroupFile) return cgroups; } -void destroyCgroup(const Path & cgroup) +static CgroupStats destroyCgroup(const Path & cgroup, bool returnStats) { - if (!pathExists(cgroup)) return; + if (!pathExists(cgroup)) return {}; + + if (!pathExists(cgroup + "/cgroup.procs")) + throw Error("'%s' is not a cgroup", cgroup); for (auto & entry : readDirectory(cgroup)) { if (entry.type != DT_DIR) continue; - destroyCgroup(cgroup + "/" + entry.name); + destroyCgroup(cgroup + "/" + entry.name, false); } int round = 1; @@ -79,8 +82,38 @@ void destroyCgroup(const Path & cgroup) round++; } + CgroupStats stats; + + if (returnStats) { + auto cpustatPath = cgroup + "/cpu.stat"; + + if (pathExists(cpustatPath)) { + for (auto & line : tokenizeString>(readFile(cpustatPath), "\n")) { + std::string_view userPrefix = "user_usec "; + if (hasPrefix(line, userPrefix)) { + auto n = string2Int(line.substr(userPrefix.size())); + if (n) stats.cpuUser = std::chrono::microseconds(*n); + } + + std::string_view systemPrefix = "system_usec "; + if (hasPrefix(line, systemPrefix)) { + auto n = string2Int(line.substr(systemPrefix.size())); + if (n) stats.cpuSystem = std::chrono::microseconds(*n); + } + } + } + + } + if (rmdir(cgroup.c_str()) == -1) throw SysError("deleting cgroup '%s'", cgroup); + + return stats; +} + +CgroupStats destroyCgroup(const Path & cgroup) +{ + return destroyCgroup(cgroup, true); } } diff --git a/src/libstore/cgroup.hh b/src/libstore/cgroup.hh index dc6758957..3ead4735f 100644 --- a/src/libstore/cgroup.hh +++ b/src/libstore/cgroup.hh @@ -2,13 +2,25 @@ #if __linux__ +#include +#include + #include "types.hh" namespace nix { std::map getCgroups(const Path & cgroupFile); -void destroyCgroup(const Path & cgroup); +struct CgroupStats +{ + std::optional cpuUser, cpuSystem; +}; + +/* Destroy the cgroup denoted by 'path'. The postcondition is that + 'path' does not exist, and thus any processes in the cgroup have + been killed. Also return statistics from the cgroup just before + destruction. */ +CgroupStats destroyCgroup(const Path & cgroup); }