Changeset: 1f6a6ff21e6b for MonetDB
URL: https://dev.monetdb.org/hg/MonetDB?cmd=changeset;node=1f6a6ff21e6b
Modified Files:
gdk/gdk_system.c
Branch: Apr2019
Log Message:
Read /sys/fs/cgroup/cpuset/cpuset.cpus if it exists to reduce number of cpus
found.
diffs (45 lines):
diff --git a/gdk/gdk_system.c b/gdk/gdk_system.c
--- a/gdk/gdk_system.c
+++ b/gdk/gdk_system.c
@@ -890,5 +890,41 @@ MT_check_nr_cores(void)
ncpus = 16;
#endif
+ /* get the number of allocated cpus from the cgroup settings */
+ FILE *f = fopen("/sys/fs/cgroup/cpuset/cpuset.cpus", "r");
+ if (f != NULL) {
+ char buf[512];
+ char *p = fgets(buf, 512, f);
+ fclose(f);
+ if (p != NULL) {
+ /* syntax is: ranges of CPU numbers separated
+ * by comma; a range is either a single CPU
+ * id, or two IDs separated by a minus; any
+ * deviation causes the file to be ignored */
+ int ncpu = 0;
+ for (;;) {
+ char *q;
+ unsigned fst = strtoul(p, &q, 10);
+ if (q == p)
+ return ncpus;
+ ncpu++;
+ if (*q == '-') {
+ p = q + 1;
+ unsigned lst = strtoul(p, &q, 10);
+ if (q == p || lst <= fst)
+ return ncpus;
+ ncpu += lst - fst;
+ }
+ if (*q == '\n')
+ break;
+ if (*q != ',')
+ return ncpus;
+ p = q + 1;
+ }
+ if (ncpu < ncpus)
+ return ncpu;
+ }
+ }
+
return ncpus;
}
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