Messages in this thread | | | From | Namhyung Kim <> | Date | Wed, 6 Jan 2021 16:38:01 +0900 | Subject | Re: [PATCH v2 01/11] perf c2c: Add dimensions for total load hit |
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Hi,
On Sun, Dec 13, 2020 at 10:39 PM Leo Yan <leo.yan@linaro.org> wrote: > > Arm SPE trace data doesn't support HITM, but we still want to explore > "perf c2c" tool to analyze cache false sharing. If without HITM tag, > the tool cannot give out accurate result for cache false sharing, a > candidate solution is to sort the total load operations and connect with > the threads info, e.g. if multiple threads hit the same cache line for > many times, this can give out the hint that it's likely to cause cache > false sharing issue. > > Unlike having HITM tag, the proposed solution is not accurate and might > introduce false positive reporting, but it's a pragmatic approach for > detecting false sharing if memory event doesn't support HITM. > > To sort with the cache line hit, this patch adds dimensions for total > load hit and the associated percentage calculation. > > Signed-off-by: Leo Yan <leo.yan@linaro.org> > --- > tools/perf/builtin-c2c.c | 112 +++++++++++++++++++++++++++++++++++++++ > 1 file changed, 112 insertions(+) > > diff --git a/tools/perf/builtin-c2c.c b/tools/perf/builtin-c2c.c > index c5babeaa3b38..3d5a2dc8b4fd 100644 > --- a/tools/perf/builtin-c2c.c > +++ b/tools/perf/builtin-c2c.c > @@ -615,6 +615,47 @@ tot_hitm_cmp(struct perf_hpp_fmt *fmt __maybe_unused, > return tot_hitm_left - tot_hitm_right; > } > > +#define TOT_LD_HIT(stats) \ > + ((stats)->ld_fbhit + \ > + (stats)->ld_l1hit + \ > + (stats)->ld_l2hit + \ > + (stats)->ld_llchit + \ > + (stats)->lcl_hitm + \ > + (stats)->rmt_hitm + \ > + (stats)->rmt_hit)
It doesn't need to be a macro, why not use a static inline function?
Thanks, Namhyung
> + > +static int tot_ld_hit_entry(struct perf_hpp_fmt *fmt, > + struct perf_hpp *hpp, > + struct hist_entry *he) > +{ > + struct c2c_hist_entry *c2c_he; > + int width = c2c_width(fmt, hpp, he->hists); > + unsigned int tot_hit; > + > + c2c_he = container_of(he, struct c2c_hist_entry, he); > + tot_hit = TOT_LD_HIT(&c2c_he->stats); > + > + return scnprintf(hpp->buf, hpp->size, "%*u", width, tot_hit); > +} > + > +static int64_t tot_ld_hit_cmp(struct perf_hpp_fmt *fmt __maybe_unused, > + struct hist_entry *left, > + struct hist_entry *right) > +{ > + struct c2c_hist_entry *c2c_left; > + struct c2c_hist_entry *c2c_right; > + uint64_t tot_hit_left; > + uint64_t tot_hit_right; > + > + c2c_left = container_of(left, struct c2c_hist_entry, he); > + c2c_right = container_of(right, struct c2c_hist_entry, he); > + > + tot_hit_left = TOT_LD_HIT(&c2c_left->stats); > + tot_hit_right = TOT_LD_HIT(&c2c_right->stats); > + > + return tot_hit_left - tot_hit_right; > +} > + > #define STAT_FN_ENTRY(__f) \ > static int \ > __f ## _entry(struct perf_hpp_fmt *fmt, struct perf_hpp *hpp, \ > @@ -860,6 +901,58 @@ percent_hitm_cmp(struct perf_hpp_fmt *fmt __maybe_unused, > return per_left - per_right; > } > > +static double percent_tot_ld_hit(struct c2c_hist_entry *c2c_he) > +{ > + struct c2c_hists *hists; > + int tot = 0, st = 0; > + > + hists = container_of(c2c_he->he.hists, struct c2c_hists, hists); > + > + st = TOT_LD_HIT(&c2c_he->stats); > + tot = TOT_LD_HIT(&hists->stats); > + > + return tot ? (double) st * 100 / tot : 0; > +} > + > +static int > +percent_tot_ld_hit_entry(struct perf_hpp_fmt *fmt, struct perf_hpp *hpp, > + struct hist_entry *he) > +{ > + struct c2c_hist_entry *c2c_he; > + int width = c2c_width(fmt, hpp, he->hists); > + char buf[10]; > + double per; > + > + c2c_he = container_of(he, struct c2c_hist_entry, he); > + per = percent_tot_ld_hit(c2c_he); > + return scnprintf(hpp->buf, hpp->size, "%*s", width, PERC_STR(buf, per)); > +} > + > +static int > +percent_tot_ld_hit_color(struct perf_hpp_fmt *fmt, struct perf_hpp *hpp, > + struct hist_entry *he) > +{ > + return percent_color(fmt, hpp, he, percent_tot_ld_hit); > +} > + > +static int64_t > +percent_tot_ld_hit_cmp(struct perf_hpp_fmt *fmt __maybe_unused, > + struct hist_entry *left, struct hist_entry *right) > +{ > + struct c2c_hist_entry *c2c_left; > + struct c2c_hist_entry *c2c_right; > + double per_left; > + double per_right; > + > + c2c_left = container_of(left, struct c2c_hist_entry, he); > + c2c_right = container_of(right, struct c2c_hist_entry, he); > + > + per_left = percent_tot_ld_hit(c2c_left); > + per_right = percent_tot_ld_hit(c2c_right); > + > + return per_left - per_right; > +} > + > static struct c2c_stats *he_stats(struct hist_entry *he) > { > struct c2c_hist_entry *c2c_he; > @@ -1412,6 +1505,14 @@ static struct c2c_dimension dim_ld_rmthit = { > .width = 8, > }; > > +static struct c2c_dimension dim_tot_ld_hit = { > + .header = HEADER_BOTH("Load Hit", "Total"), > + .name = "tot_ld_hit", > + .cmp = tot_ld_hit_cmp, > + .entry = tot_ld_hit_entry, > + .width = 8, > +}; > + > static struct c2c_dimension dim_tot_recs = { > .header = HEADER_BOTH("Total", "records"), > .name = "tot_recs", > @@ -1460,6 +1561,15 @@ static struct c2c_dimension dim_percent_lcl_hitm = { > .width = 7, > }; > > +static struct c2c_dimension dim_percent_tot_ld_hit = { > + .header = HEADER_BOTH("Load Hit", "Pct"), > + .name = "percent_tot_ld_hit", > + .cmp = percent_tot_ld_hit_cmp, > + .entry = percent_tot_ld_hit_entry, > + .color = percent_tot_ld_hit_color, > + .width = 8, > +}; > + > static struct c2c_dimension dim_percent_stores_l1hit = { > .header = HEADER_SPAN("-- Store Refs --", "L1 Hit", 1), > .name = "percent_stores_l1hit", > @@ -1615,11 +1725,13 @@ static struct c2c_dimension *dimensions[] = { > &dim_ld_l2hit, > &dim_ld_llchit, > &dim_ld_rmthit, > + &dim_tot_ld_hit, > &dim_tot_recs, > &dim_tot_loads, > &dim_percent_hitm, > &dim_percent_rmt_hitm, > &dim_percent_lcl_hitm, > + &dim_percent_tot_ld_hit, > &dim_percent_stores_l1hit, > &dim_percent_stores_l1miss, > &dim_dram_lcl, > -- > 2.17.1 >
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