Mirror of GNU Guix
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#include "types.hh"
#include "util.hh"
#include "affinity.hh"
#if HAVE_SCHED_H
#include <sched.h>
#endif
namespace nix {
#if HAVE_SCHED_SETAFFINITY
static bool didSaveAffinity = false;
static cpu_set_t savedAffinity;
#endif
void setAffinityTo(int cpu)
{
#if HAVE_SCHED_SETAFFINITY
if (sched_getaffinity(0, sizeof(cpu_set_t), &savedAffinity) == -1) return;
didSaveAffinity = true;
printMsg(lvlDebug, format("locking this thread to CPU %1%") % cpu);
cpu_set_t newAffinity;
CPU_ZERO(&newAffinity);
CPU_SET(cpu, &newAffinity);
if (sched_setaffinity(0, sizeof(cpu_set_t), &newAffinity) == -1)
printMsg(lvlError, format("failed to lock thread to CPU %1%") % cpu);
#endif
}
int lockToCurrentCPU()
{
#if HAVE_SCHED_SETAFFINITY
int cpu = sched_getcpu();
if (cpu != -1) setAffinityTo(cpu);
return cpu;
#else
return -1;
#endif
}
void restoreAffinity()
{
#if HAVE_SCHED_SETAFFINITY
if (!didSaveAffinity) return;
if (sched_setaffinity(0, sizeof(cpu_set_t), &savedAffinity) == -1)
printMsg(lvlError, "failed to restore affinity %1%");
#endif
}
}