From 936f9d45baf474358346666ed9ad7f56960bb455 Mon Sep 17 00:00:00 2001 From: Eelco Dolstra Date: Fri, 6 Sep 2013 16:36:56 +0200 Subject: [PATCH] Don't apply the CPU affinity hack to nix-shell (and other Perl programs) As discovered by Todd Veldhuizen, the shell started by nix-shell has its affinity set to a single CPU. This is because nix-shell connects to the Nix daemon, which causes the affinity hack to be applied. So we turn this off for Perl programs. --- perl/lib/Nix/Store.xs | 1 + src/libstore/globals.cc | 1 + src/libstore/globals.hh | 3 +++ src/libstore/remote-store.cc | 2 +- src/libutil/affinity.cc | 11 +++++------ 5 files changed, 11 insertions(+), 7 deletions(-) diff --git a/perl/lib/Nix/Store.xs b/perl/lib/Nix/Store.xs index 8154bcbb0..c449ed524 100644 --- a/perl/lib/Nix/Store.xs +++ b/perl/lib/Nix/Store.xs @@ -20,6 +20,7 @@ void doInit() if (!store) { try { settings.processEnvironment(); + settings.lockCPU = false; store = openStore(); } catch (Error & e) { croak(e.what()); diff --git a/src/libstore/globals.cc b/src/libstore/globals.cc index aeb52e1a8..7e0157cd3 100644 --- a/src/libstore/globals.cc +++ b/src/libstore/globals.cc @@ -54,6 +54,7 @@ Settings::Settings() gcKeepDerivations = true; autoOptimiseStore = false; envKeepDerivations = false; + lockCPU = getEnv("NIX_AFFINITY_HACK", "1") == "1"; } diff --git a/src/libstore/globals.hh b/src/libstore/globals.hh index 50b61725c..cbc6d4e98 100644 --- a/src/libstore/globals.hh +++ b/src/libstore/globals.hh @@ -183,6 +183,9 @@ struct Settings { (to prevent them from being GCed). */ bool envKeepDerivations; + /* Whether to lock the Nix client and worker to the same CPU. */ + bool lockCPU; + private: SettingsMap settings, overrides; diff --git a/src/libstore/remote-store.cc b/src/libstore/remote-store.cc index 3764b4813..3017254ba 100644 --- a/src/libstore/remote-store.cc +++ b/src/libstore/remote-store.cc @@ -73,7 +73,7 @@ void RemoteStore::openConnection(bool reserveSpace) writeInt(PROTOCOL_VERSION, to); if (GET_PROTOCOL_MINOR(daemonVersion) >= 14) { - int cpu = lockToCurrentCPU(); + int cpu = settings.lockCPU ? lockToCurrentCPU() : -1; if (cpu != -1) { writeInt(1, to); writeInt(cpu, to); diff --git a/src/libutil/affinity.cc b/src/libutil/affinity.cc index 7a6310cad..3e21f43a2 100644 --- a/src/libutil/affinity.cc +++ b/src/libutil/affinity.cc @@ -33,13 +33,12 @@ void setAffinityTo(int cpu) int lockToCurrentCPU() { #if HAVE_SCHED_SETAFFINITY - if (getEnv("NIX_AFFINITY_HACK", "1") == "1") { - int cpu = sched_getcpu(); - if (cpu != -1) setAffinityTo(cpu); - return cpu; - } -#endif + int cpu = sched_getcpu(); + if (cpu != -1) setAffinityTo(cpu); + return cpu; +#else return -1; +#endif }