src/CpuAffinitySet.cc

   1 /*
   2  * Copyright (C) 1996-2023 The Squid Software Foundation and contributors
   3  *
   4  * Squid software is distributed under GPLv2+ license and includes
   5  * contributions from numerous individuals and organizations.
   6  * Please see the COPYING and CONTRIBUTORS files for details.
   7  */
   8
   9 /* DEBUG: section 54    Interprocess Communication */
  10
  11 #include "squid.h"
  12 #include "base/TextException.h"
  13 #include "CpuAffinitySet.h"
  14 #include "debug/Stream.h"
  15 #include "util.h"
  16
  17 #include <cerrno>
  18 #include <cstring>
  19
  20 CpuAffinitySet::CpuAffinitySet()
  21 {
  22     CPU_ZERO(&theCpuSet);
  23     CPU_ZERO(&theOrigCpuSet);
  24 }
  25
  26 void
  27 CpuAffinitySet::apply()
  28 {
  29     Must(CPU_COUNT(&theCpuSet) > 0); // CPU affinity mask set
  30     Must(!applied());
  31
  32     bool success = false;
  33     if (sched_getaffinity(0, sizeof(theOrigCpuSet), &theOrigCpuSet)) {
  34         int xerrno = errno;
  35         debugs(54, DBG_IMPORTANT, "ERROR: failed to get CPU affinity for "
  36                "process PID " << getpid() << ", ignoring CPU affinity for "
  37                "this process: " << xstrerr(xerrno));
  38     } else {
  39         cpu_set_t cpuSet;
  40         memcpy(&cpuSet, &theCpuSet, sizeof(cpuSet));
  41         CPU_AND(&cpuSet, &cpuSet, &theOrigCpuSet);
  42         if (CPU_COUNT(&cpuSet) <= 0) {
  43             debugs(54, DBG_IMPORTANT, "ERROR: invalid CPU affinity for process "
  44                    "PID " << getpid() << ", may be caused by an invalid core in "
  45                    "'cpu_affinity_map' or by external affinity restrictions");
  46         } else if (sched_setaffinity(0, sizeof(cpuSet), &cpuSet)) {
  47             int xerrno = errno;
  48             debugs(54, DBG_IMPORTANT, "ERROR: failed to set CPU affinity for "
  49                    "process PID " << getpid() << ": " << xstrerr(xerrno));
  50         } else
  51             success = true;
  52     }
  53     if (!success)
  54         CPU_ZERO(&theOrigCpuSet);
  55 }
  56
  57 void
  58 CpuAffinitySet::undo()
  59 {
  60     if (applied()) {
  61         if (sched_setaffinity(0, sizeof(theOrigCpuSet), &theOrigCpuSet)) {
  62             int xerrno = errno;
  63             debugs(54, DBG_IMPORTANT, "ERROR: failed to restore original CPU "
  64                    "affinity for process PID " << getpid() << ": " <<
  65                    xstrerr(xerrno));
  66         }
  67         CPU_ZERO(&theOrigCpuSet);
  68     }
  69 }
  70
  71 bool
  72 CpuAffinitySet::applied()
  73 {
  74     // NOTE: cannot be const.
  75     // According to CPU_SET(3) and, apparently, on some systems (e.g.,
  76     // OpenSuSE 10.3) CPU_COUNT macro expects a non-const argument.
  77     return (CPU_COUNT(&theOrigCpuSet) > 0);
  78 }
  79
  80 void
  81 CpuAffinitySet::set(const cpu_set_t &aCpuSet)
  82 {
  83     memcpy(&theCpuSet, &aCpuSet, sizeof(theCpuSet));
  84 }
  85