Date: Sun, 28 Jun 2009 15:44:47 -0500 From: Dan Nelson <dnelson@allantgroup.com> To: msnkipa@mail.ru Cc: freebsd-hackers@freebsd.org Subject: Re: Can I bind POSIX thread to cpu core? Message-ID: <20090628204446.GI76275@dan.emsphone.com> In-Reply-To: <E1MKyyu-0002jv-00.msnkipa-mail-ru@f103.mail.ru> References: <E1MKyyu-0002jv-00.msnkipa-mail-ru@f103.mail.ru>
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In the last episode (Jun 28): > I have system with 4 core cpu. How can I bind POSIX thread to the one > core? I mean that this thread can be executed on the fixed core. See the cpuset(2) and cpuset_setaffinity(2) manpages. Something like this should work: #include <err.h> #include <stdio.h> #include <sys/param.h> #include <sys/cpuset.h> int main(void) { int i; cpuset_t myset; /* Get CPU mask for the current thread */ if (cpuset_getaffinity(CPU_LEVEL_WHICH, CPU_WHICH_TID, -1, sizeof(myset), &myset) == -1) err(1, "getaffinity failed"); /* Find first available CPU - don't assume CPU0 is always available */ for (i = 0; i < CPU_SETSIZE; i++) if (CPU_ISSET(i, &myset)) break; if (i == CPU_SETSIZE) err(1, "Not allowed to run on any CPUs? How did I print this, then?"); /* Set new CPU mask */ printf ("Setting affinity to CPU %d\n", i); CPU_ZERO(&myset); CPU_SET(i, &myset); if (cpuset_setaffinity(CPU_LEVEL_WHICH, CPU_WHICH_TID, -1, sizeof(myset), &myset) == -1) warn("setaffinity failed"); /* Do CPU-intensive stuff here */ return 0; } -- Dan Nelson dnelson@allantgroup.com
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