From 31caec794c3978d55d79f715f21fb72948c9f300 Mon Sep 17 00:00:00 2001 From: Simon Marlow Date: Wed, 18 Mar 2009 15:47:19 +0000 Subject: [PATCH] Set thread affinity with +RTS -qa (only on Linux so far) --- configure.ac | 4 ++-- includes/OSThreads.h | 4 ++-- includes/RtsFlags.h | 1 + rts/RtsFlags.c | 6 ++++++ rts/Schedule.c | 4 ++++ rts/posix/OSThreads.c | 27 ++++++++++++++++++++++++++- rts/win32/OSThreads.c | 6 ++++++ 7 files changed, 47 insertions(+), 5 deletions(-) diff --git a/configure.ac b/configure.ac index 85e0617..4067335 100644 --- a/configure.ac +++ b/configure.ac @@ -1029,7 +1029,7 @@ dnl off_t, because it will affect the result of that test. AC_SYS_LARGEFILE dnl ** check for specific header (.h) files that we are interested in -AC_CHECK_HEADERS([bfd.h ctype.h dirent.h dlfcn.h errno.h fcntl.h grp.h limits.h locale.h nlist.h pthread.h pwd.h signal.h sys/mman.h sys/resource.h sys/time.h sys/timeb.h sys/timers.h sys/times.h sys/utsname.h sys/wait.h termios.h time.h utime.h windows.h winsock.h]) +AC_CHECK_HEADERS([bfd.h ctype.h dirent.h dlfcn.h errno.h fcntl.h grp.h limits.h locale.h nlist.h pthread.h pwd.h signal.h sys/mman.h sys/resource.h sys/time.h sys/timeb.h sys/timers.h sys/times.h sys/utsname.h sys/wait.h termios.h time.h utime.h windows.h winsock.h sched.h]) dnl ** check if it is safe to include both and AC_HEADER_TIME @@ -1107,7 +1107,7 @@ fi dnl ** check for more functions dnl ** The following have been verified to be used in ghc/, but might be used somewhere else, too. -AC_CHECK_FUNCS([getclock getrusage gettimeofday setitimer siginterrupt sysconf times ctime_r]) +AC_CHECK_FUNCS([getclock getrusage gettimeofday setitimer siginterrupt sysconf times ctime_r, sched_setaffinity]) AC_TRY_RUN([ #include diff --git a/includes/OSThreads.h b/includes/OSThreads.h index 73ef4d2..f5c434f 100644 --- a/includes/OSThreads.h +++ b/includes/OSThreads.h @@ -186,8 +186,8 @@ void setThreadLocalVar (ThreadLocalKey *key, void *value); void freeThreadLocalKey (ThreadLocalKey *key); // Processors and affinity -nat getNumberOfProcessors (void); - +nat getNumberOfProcessors (void); +void setThreadAffinity (nat n, nat m); #endif // !CMINUSMINUS #else diff --git a/includes/RtsFlags.h b/includes/RtsFlags.h index 7709787..348a8f5 100644 --- a/includes/RtsFlags.h +++ b/includes/RtsFlags.h @@ -192,6 +192,7 @@ struct PAR_FLAGS { rtsBool parGcGen; /* do parallel GC in this generation * and higher only */ rtsBool parGcLoadBalancing; /* do load-balancing in parallel GC */ + rtsBool setAffinity; /* force thread affinity with CPUs */ }; #endif /* THREADED_RTS */ diff --git a/rts/RtsFlags.c b/rts/RtsFlags.c index 3fac86b..6a8c692 100644 --- a/rts/RtsFlags.c +++ b/rts/RtsFlags.c @@ -233,6 +233,7 @@ void initRtsFlagsDefaults(void) RtsFlags.ParFlags.parGcEnabled = 1; RtsFlags.ParFlags.parGcGen = 1; RtsFlags.ParFlags.parGcLoadBalancing = 1; + RtsFlags.ParFlags.setAffinity = 0; #endif #ifdef PAR @@ -476,6 +477,8 @@ usage_text[] = { " -N Determine the number of processors to use automatically", " -q1 Use one OS thread for GC (turns off parallel GC)", " -qg Use parallel GC only for generations >= (default: 1)", +" -qb Disable load-balancing in the parallel GC", +" -qa Use the OS to set thread affinity", " -qm Don't automatically migrate threads between CPUs", " -qw Migrate a thread to the current CPU when it is woken up", #endif @@ -1233,6 +1236,9 @@ error = rtsTrue; case 'b': RtsFlags.ParFlags.parGcLoadBalancing = rtsFalse; break; + case 'a': + RtsFlags.ParFlags.setAffinity = rtsTrue; + break; case 'm': RtsFlags.ParFlags.migrate = rtsFalse; break; diff --git a/rts/Schedule.c b/rts/Schedule.c index 666b59e..636b517 100644 --- a/rts/Schedule.c +++ b/rts/Schedule.c @@ -2125,6 +2125,10 @@ workerStart(Task *task) cap = task->cap; RELEASE_LOCK(&task->lock); + if (RtsFlags.ParFlags.setAffinity) { + setThreadAffinity(cap->no, n_capabilities); + } + // set the thread-local pointer to the Task: taskEnter(task); diff --git a/rts/posix/OSThreads.c b/rts/posix/OSThreads.c index 6eb2d2b..f15fc95 100644 --- a/rts/posix/OSThreads.c +++ b/rts/posix/OSThreads.c @@ -7,8 +7,9 @@ * * --------------------------------------------------------------------------*/ -#if defined(DEBUG) && defined(__linux__) +#if defined(__linux__) /* We want GNU extensions in DEBUG mode for mutex error checking */ +/* We also want the affinity API, which requires _GNU_SOURCE */ #define _GNU_SOURCE #endif @@ -26,6 +27,10 @@ #error pthreads.h is required for the threaded RTS on Posix platforms #endif +#if defined(HAVE_SCHED_H) +#include +#endif + /* * This (allegedly) OS threads independent layer was initially * abstracted away from code that used Pthreads, so the functions @@ -197,6 +202,26 @@ getNumberOfProcessors (void) return nproc; } +// Schedules the thread to run on CPU n of m. m may be less than the +// number of physical CPUs, in which case, the thread will be allowed +// to run on CPU n, n+m, n+2m etc. +void +setThreadAffinity (nat n, nat m) +{ +#if defined(HAVE_SCHED_H) && defined(HAVE_SCHED_SETAFFINITY) + nat nproc; + cpu_set_t cs; + nat i; + + nproc = getNumberOfProcessors(); + CPU_ZERO(&cs); + for (i = n; i < nproc; i+=m) { + CPU_SET(n, &cs); + } + sched_setaffinity(0, sizeof(cpu_set_t), &cs); +#endif +} + #else /* !defined(THREADED_RTS) */ int diff --git a/rts/win32/OSThreads.c b/rts/win32/OSThreads.c index 929b817..c18bab2 100644 --- a/rts/win32/OSThreads.c +++ b/rts/win32/OSThreads.c @@ -246,6 +246,12 @@ getNumberOfProcessors (void) return nproc; } +void +setThreadAffinity (nat n STG_UNUSED, nat m STG_UNUSED) +{ + /* ToDo */ +} + #else /* !defined(THREADED_RTS) */ int -- 1.7.10.4