[PATCH v2 7/9] perf c2c: Correct LLC load hit metrics

From: Leo Yan
Date: Thu Oct 15 2020 - 10:46:45 EST


"rmt_hit" is accounted into two metrics: one is accounted into the
metrics "LLC Ld Miss" (see the function llc_miss() for calculation
"llcmiss"); and it's accounted into metrics "LLC Load Hit". Thus,
for the literal meaning, it is contradictory that "rmt_hit" is
accounted for both "LLC Ld Miss" (LLC miss) and "LLC Load Hit"
(LLC hit).

Thus this is easily to introduce confusion: "LLC Load Hit" gives
impression that all items belong to it are LLC hit; in fact "rmt_hit"
is LLC miss and remote cache hit.

To give out clear semantics for metric "LLC Load Hit", "rmt_hit" is
moved out from it and changes "LLC Load Hit" to contain two items:

LLC Load Hit = LLC's hit ("ld_llchit") + LLC's hitm ("lcl_hitm")

For output alignment, adjusts the header for "LLC Load Hit".

Signed-off-by: Leo Yan <leo.yan@xxxxxxxxxx>
Tested-by: Joe Mario <jmario@xxxxxxxxxx>
---
tools/perf/builtin-c2c.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/perf/builtin-c2c.c b/tools/perf/builtin-c2c.c
index 2292261b40a2..61fb939a4e70 100644
--- a/tools/perf/builtin-c2c.c
+++ b/tools/perf/builtin-c2c.c
@@ -1432,7 +1432,7 @@ static struct c2c_dimension dim_ld_l2hit = {
};

static struct c2c_dimension dim_ld_llchit = {
- .header = HEADER_SPAN("-- LLC Load Hit --", "LclHit", 1),
+ .header = HEADER_SPAN("- LLC Load Hit --", "LclHit", 1),
.name = "ld_lclhit",
.cmp = ld_llchit_cmp,
.entry = ld_llchit_entry,
@@ -2853,7 +2853,7 @@ static int perf_c2c__report(int argc, const char **argv)
"tot_stores,"
"stores_l1hit,stores_l1miss,"
"ld_fbhit,ld_l1hit,ld_l2hit,"
- "ld_lclhit,ld_rmthit,"
+ "ld_lclhit,lcl_hitm,"
"ld_llcmiss,"
"dram_lcl,dram_rmt",
c2c.display == DISPLAY_TOT ? "tot_hitm" :
--
2.17.1