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authorMichael Petlan <mpetlan@redhat.com>2019-12-08 17:20:56 +0100
committerArnaldo Carvalho de Melo <acme@redhat.com>2019-12-11 12:28:14 -0300
commit28707826877f84bce0977845ea529cbdd08e4e8d (patch)
tree1c9955959fcb9d6add0e2593308ad9e0fa789123 /tools/perf/util/header.c
parentperf metricgroup: Fix printing event names of metric group with multiple events (diff)
downloadlinux-dev-28707826877f84bce0977845ea529cbdd08e4e8d.tar.xz
linux-dev-28707826877f84bce0977845ea529cbdd08e4e8d.zip
perf header: Fix false warning when there are no duplicate cache entries
Before this patch, perf expected that there might be NPROC*4 unique cache entries at max, however, it also expected that some of them would be shared and/or of the same size, thus the final number of entries would be reduced to be lower than NPROC*4. In case the number of entries hadn't been reduced (was NPROC*4), the warning was printed. However, some systems might have unusual cache topology, such as the following two-processor KVM guest: cpu level shared_cpu_list size 0 1 0 32K 0 1 0 64K 0 2 0 512K 0 3 0 8192K 1 1 1 32K 1 1 1 64K 1 2 1 512K 1 3 1 8192K This KVM guest has 8 (NPROC*4) unique cache entries, which used to make perf printing the message, although there actually aren't "way too many cpu caches". v2: Removing unused argument. v3: Unifying the way we obtain number of cpus. v4: Removed '& UINT_MAX' construct which is redundant. Signed-off-by: Michael Petlan <mpetlan@redhat.com> Acked-by: Jiri Olsa <jolsa@redhat.com> LPU-Reference: 20191208162056.20772-1-mpetlan@redhat.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/util/header.c')
-rw-r--r--tools/perf/util/header.c21
1 files changed, 6 insertions, 15 deletions
diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index 4d39a75551a0..93ad27830e2b 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -1089,21 +1089,18 @@ static void cpu_cache_level__fprintf(FILE *out, struct cpu_cache_level *c)
fprintf(out, "L%d %-15s %8s [%s]\n", c->level, c->type, c->size, c->map);
}
-static int build_caches(struct cpu_cache_level caches[], u32 size, u32 *cntp)
+#define MAX_CACHE_LVL 4
+
+static int build_caches(struct cpu_cache_level caches[], u32 *cntp)
{
u32 i, cnt = 0;
- long ncpus;
u32 nr, cpu;
u16 level;
- ncpus = sysconf(_SC_NPROCESSORS_CONF);
- if (ncpus < 0)
- return -1;
-
- nr = (u32)(ncpus & UINT_MAX);
+ nr = cpu__max_cpu();
for (cpu = 0; cpu < nr; cpu++) {
- for (level = 0; level < 10; level++) {
+ for (level = 0; level < MAX_CACHE_LVL; level++) {
struct cpu_cache_level c;
int err;
@@ -1123,18 +1120,12 @@ static int build_caches(struct cpu_cache_level caches[], u32 size, u32 *cntp)
caches[cnt++] = c;
else
cpu_cache_level__free(&c);
-
- if (WARN_ONCE(cnt == size, "way too many cpu caches.."))
- goto out;
}
}
- out:
*cntp = cnt;
return 0;
}
-#define MAX_CACHE_LVL 4
-
static int write_cache(struct feat_fd *ff,
struct evlist *evlist __maybe_unused)
{
@@ -1143,7 +1134,7 @@ static int write_cache(struct feat_fd *ff,
u32 cnt = 0, i, version = 1;
int ret;
- ret = build_caches(caches, max_caches, &cnt);
+ ret = build_caches(caches, &cnt);
if (ret)
goto out;