[PATCH] Perf stat: Fix the ratio comments of cache miss-events

From: Lin Feng
Date: Thu Feb 13 2020 - 04:33:10 EST


Perf stat displays miss ratio of L1-dcache, L1-icache, dTLB cache,
iTLB cache and LL-cache, while the comments for them seem a bit
misleading. Take L1-dcache for example, its miss ratio
is caculated as "L1-dcache-load-misses/L1-dcache-loads". So "of all
L1-dcache hits" is unsuitable to describe it, and "of all L1-dcache
accesses/references" seems better.

285,132,521 cache-misses # 53.696 % of all cache refs [83.34%]
531,015,219 cache-references [83.20%]
220,465,183 LLC-load-misses # 72.33% of all LL-cache miss [83.44%]
^^^^
304,787,745 LLC-loads [66.60%]

There is an old patch here https://lkml.org/lkml/2019/11/16/37, but
seems not upstreamed yet. This patch follows suggestions by Arnaldo.
But one difference is using "refs" to follow the convention because
there is comment also for cache-misses event which uses
"of all cache refs".
The comments of L1-icache, dTLB cache, iTLB cache and LL-cache are
fixed in the same way.

P.S. Liu and Andi if you don't mind this patch adds your Reviewed-by
and Signed-off-by, thanks.

Reviewed-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Signed-off-by: Qi Liu <liuqi115@xxxxxxxxxxxxx>
Signed-off-by: Lin Feng <linf@xxxxxxxxxx>
---
tools/perf/util/stat-shadow.c | 20 ++++++++++----------
1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/tools/perf/util/stat-shadow.c b/tools/perf/util/stat-shadow.c
index 2c41d47f6f83..070e9749e934 100644
--- a/tools/perf/util/stat-shadow.c
+++ b/tools/perf/util/stat-shadow.c
@@ -506,7 +506,7 @@ static void print_l1_dcache_misses(struct perf_stat_config *config,

color = get_ratio_color(GRC_CACHE_MISSES, ratio);

- out->print_metric(config, out->ctx, color, "%7.2f%%", "of all L1-dcache hits", ratio);
+ out->print_metric(config, out->ctx, color, "%7.2f%%", "of all L1-dcache refs", ratio);
}

static void print_l1_icache_misses(struct perf_stat_config *config,
@@ -527,7 +527,7 @@ static void print_l1_icache_misses(struct perf_stat_config *config,
ratio = avg / total * 100.0;

color = get_ratio_color(GRC_CACHE_MISSES, ratio);
- out->print_metric(config, out->ctx, color, "%7.2f%%", "of all L1-icache hits", ratio);
+ out->print_metric(config, out->ctx, color, "%7.2f%%", "of all L1-icache refs", ratio);
}

static void print_dtlb_cache_misses(struct perf_stat_config *config,
@@ -547,7 +547,7 @@ static void print_dtlb_cache_misses(struct perf_stat_config *config,
ratio = avg / total * 100.0;

color = get_ratio_color(GRC_CACHE_MISSES, ratio);
- out->print_metric(config, out->ctx, color, "%7.2f%%", "of all dTLB cache hits", ratio);
+ out->print_metric(config, out->ctx, color, "%7.2f%%", "of all dTLB cache refs", ratio);
}

static void print_itlb_cache_misses(struct perf_stat_config *config,
@@ -567,7 +567,7 @@ static void print_itlb_cache_misses(struct perf_stat_config *config,
ratio = avg / total * 100.0;

color = get_ratio_color(GRC_CACHE_MISSES, ratio);
- out->print_metric(config, out->ctx, color, "%7.2f%%", "of all iTLB cache hits", ratio);
+ out->print_metric(config, out->ctx, color, "%7.2f%%", "of all iTLB cache refs", ratio);
}

static void print_ll_cache_misses(struct perf_stat_config *config,
@@ -587,7 +587,7 @@ static void print_ll_cache_misses(struct perf_stat_config *config,
ratio = avg / total * 100.0;

color = get_ratio_color(GRC_CACHE_MISSES, ratio);
- out->print_metric(config, out->ctx, color, "%7.2f%%", "of all LL-cache hits", ratio);
+ out->print_metric(config, out->ctx, color, "%7.2f%%", "of all LL-cache refs", ratio);
}

/*
@@ -872,7 +872,7 @@ void perf_stat__print_shadow_stats(struct perf_stat_config *config,
if (runtime_stat_n(st, STAT_L1_DCACHE, ctx, cpu) != 0)
print_l1_dcache_misses(config, cpu, evsel, avg, out, st);
else
- print_metric(config, ctxp, NULL, NULL, "of all L1-dcache hits", 0);
+ print_metric(config, ctxp, NULL, NULL, "of all L1-dcache refs", 0);
} else if (
evsel->core.attr.type == PERF_TYPE_HW_CACHE &&
evsel->core.attr.config == ( PERF_COUNT_HW_CACHE_L1I |
@@ -882,7 +882,7 @@ void perf_stat__print_shadow_stats(struct perf_stat_config *config,
if (runtime_stat_n(st, STAT_L1_ICACHE, ctx, cpu) != 0)
print_l1_icache_misses(config, cpu, evsel, avg, out, st);
else
- print_metric(config, ctxp, NULL, NULL, "of all L1-icache hits", 0);
+ print_metric(config, ctxp, NULL, NULL, "of all L1-icache refs", 0);
} else if (
evsel->core.attr.type == PERF_TYPE_HW_CACHE &&
evsel->core.attr.config == ( PERF_COUNT_HW_CACHE_DTLB |
@@ -892,7 +892,7 @@ void perf_stat__print_shadow_stats(struct perf_stat_config *config,
if (runtime_stat_n(st, STAT_DTLB_CACHE, ctx, cpu) != 0)
print_dtlb_cache_misses(config, cpu, evsel, avg, out, st);
else
- print_metric(config, ctxp, NULL, NULL, "of all dTLB cache hits", 0);
+ print_metric(config, ctxp, NULL, NULL, "of all dTLB cache refs", 0);
} else if (
evsel->core.attr.type == PERF_TYPE_HW_CACHE &&
evsel->core.attr.config == ( PERF_COUNT_HW_CACHE_ITLB |
@@ -902,7 +902,7 @@ void perf_stat__print_shadow_stats(struct perf_stat_config *config,
if (runtime_stat_n(st, STAT_ITLB_CACHE, ctx, cpu) != 0)
print_itlb_cache_misses(config, cpu, evsel, avg, out, st);
else
- print_metric(config, ctxp, NULL, NULL, "of all iTLB cache hits", 0);
+ print_metric(config, ctxp, NULL, NULL, "of all iTLB cache refs", 0);
} else if (
evsel->core.attr.type == PERF_TYPE_HW_CACHE &&
evsel->core.attr.config == ( PERF_COUNT_HW_CACHE_LL |
@@ -912,7 +912,7 @@ void perf_stat__print_shadow_stats(struct perf_stat_config *config,
if (runtime_stat_n(st, STAT_LL_CACHE, ctx, cpu) != 0)
print_ll_cache_misses(config, cpu, evsel, avg, out, st);
else
- print_metric(config, ctxp, NULL, NULL, "of all LL-cache hits", 0);
+ print_metric(config, ctxp, NULL, NULL, "of all LL-cache refs", 0);
} else if (perf_evsel__match(evsel, HARDWARE, HW_CACHE_MISSES)) {
total = runtime_stat_avg(st, STAT_CACHEREFS, ctx, cpu);

--
2.20.1