usr.bin/dsynth/numa.c

   1 /*
   2  * Copyright (c) 2022 The DragonFly Project.  All rights reserved.
   3  *
   4  * This code is derived from software contributed to The DragonFly Project
   5  * by Matthew Dillon <dillon@backplane.com>
   6  *
   7  * This code uses concepts and configuration based on 'synth', by
   8  * John R. Marino <draco@marino.st>, which was written in ada.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  *
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions and the following disclaimer.
  16  * 2. Redistributions in binary form must reproduce the above copyright
  17  *    notice, this list of conditions and the following disclaimer in
  18  *    the documentation and/or other materials provided with the
  19  *    distribution.
  20  * 3. Neither the name of The DragonFly Project nor the names of its
  21  *    contributors may be used to endorse or promote products derived
  22  *    from this software without specific, prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  25  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  26  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  27  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  28  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  29  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  30  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  31  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  32  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  33  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  34  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  35  * SUCH DAMAGE.
  36  */
  37 /*
  38  * Put builders into (numa) cpu domains to improve cache interactions
  39  * (This is totally optional)
  40  */
  41 #include "dsynth.h"
  42
  43 /*
  44  * Number of NUMA domains or integral multiple of same.  Recommend a
  45  * value of 0 (disabled), 2 or 4.  Set with Numa_setsize parameter.
  46  */
  47 int NumaSetSize = 0;
  48
  49 /*
  50  * Set the domain for the given slot number.  -1 == reset to default.
  51  */
  52 void
  53 setNumaDomain(int slot)
  54 {
  55         static int numa_initialized;
  56         static cpu_set_t defset;
  57
  58         /*
  59          * Auto-initialization (0) -> Enabled (1) or Disabled (-1)
  60          */
  61         if (numa_initialized == 0) {
  62                 if (NumaSetSize <= 1) {
  63                         /*
  64                          * Disabled
  65                          */
  66                         numa_initialized = -1;
  67                 } else if (pthread_getaffinity_np(pthread_self(),
  68                                                   sizeof(defset), &defset) != 0)
  69                 {
  70                         /*
  71                          * Missing pthreads support
  72                          */
  73                         dlog(DLOG_ALL,
  74                              "Warning: pthread_*affinity*() "
  75                              "not supported\n");
  76                         numa_initialized = -1;
  77                 } else {
  78                         /*
  79                          * Operational, default set saved
  80                          */
  81                         numa_initialized = 1;
  82                 }
  83         }
  84
  85         /*
  86          * Do nothing if disabled
  87          */
  88         if (numa_initialized < 0)
  89                 return;
  90
  91         /*
  92          * Set domain for requested slot number or -1 to return to default
  93          */
  94         if (slot < 0) {
  95                 /*
  96                  * Return to default
  97                  */
  98                 pthread_setaffinity_np(pthread_self(), sizeof(defset), &defset);
  99         } else if (NumCores <= NumaSetSize * 2) {
 100                 /*
 101                  * Not enough cores to partition
 102                  */
 103                 /* do nothing */
 104         } else {
 105                 /*
 106                  * Set cpumask to N-way partitioned mask of cpu threads,
 107                  * hopefully in the same NUMA domain.
 108                  *
 109                  * XXX hacked for the moment to assume a simple partitioning
 110                  * in linear blocks of cores, with the second half of the
 111                  * cpu space being the related sibling hyperthreads.
 112                  */
 113                 cpu_set_t cpuset;
 114                 int hcores = NumCores / 2;
 115                 int count = (hcores + NumaSetSize - 1) / NumaSetSize;
 116                 int i;
 117
 118                 slot = slot % NumaSetSize;
 119                 slot *= count;
 120                 slot %= hcores;
 121                 CPU_ZERO(&cpuset);
 122                 for (i = 0; i < count; ++i) {
 123                         CPU_SET(slot + i, &cpuset);
 124                         CPU_SET(slot + hcores + i, &cpuset);
 125                 }
 126                 pthread_setaffinity_np(pthread_self(), sizeof(cpuset), &cpuset);
 127         }
 128 }