Messages in this thread | | | Subject | Re: [PATCH] perf stat: Fix wrong skipping for per-die aggregation | From | "Jin, Yao" <> | Date | Thu, 24 Dec 2020 09:24:49 +0800 |
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On 12/24/2020 6:35 AM, Jiri Olsa wrote: > On Wed, Dec 16, 2020 at 03:01:46PM +0800, Jin Yao wrote: >> Uncore becomes die-scope on Xeon Cascade Lake-AP and perf has supported >> --per-die aggregation yet. >> >> One issue is found in check_per_pkg() for uncore events running on >> AP system. On cascade Lake-AP, we have: >> >> S0-D0 >> S0-D1 >> S1-D0 >> S1-D1 >> >> But in check_per_pkg(), S0-D1 and S1-D1 are skipped because the >> mask bits for S0 and S1 have been set for S0-D0 and S1-D0. It doesn't >> check die_id. So the counting for S0-D1 and S1-D1 are set to zero. >> That's not correct. >> >> root@lkp-csl-2ap4 ~# ./perf stat -a -I 1000 -e llc_misses.mem_read --per-die -- sleep 5 >> 1.001460963 S0-D0 1 1317376 Bytes llc_misses.mem_read >> 1.001460963 S0-D1 1 998016 Bytes llc_misses.mem_read >> 1.001460963 S1-D0 1 970496 Bytes llc_misses.mem_read >> 1.001460963 S1-D1 1 1291264 Bytes llc_misses.mem_read >> 2.003488021 S0-D0 1 1082048 Bytes llc_misses.mem_read >> 2.003488021 S0-D1 1 1919040 Bytes llc_misses.mem_read >> 2.003488021 S1-D0 1 890752 Bytes llc_misses.mem_read >> 2.003488021 S1-D1 1 2380800 Bytes llc_misses.mem_read >> 3.005613270 S0-D0 1 1126080 Bytes llc_misses.mem_read >> 3.005613270 S0-D1 1 2898176 Bytes llc_misses.mem_read >> 3.005613270 S1-D0 1 870912 Bytes llc_misses.mem_read >> 3.005613270 S1-D1 1 3388608 Bytes llc_misses.mem_read >> 4.007627598 S0-D0 1 1124608 Bytes llc_misses.mem_read >> 4.007627598 S0-D1 1 3884416 Bytes llc_misses.mem_read >> 4.007627598 S1-D0 1 921088 Bytes llc_misses.mem_read >> 4.007627598 S1-D1 1 4451840 Bytes llc_misses.mem_read >> 5.001479927 S0-D0 1 963328 Bytes llc_misses.mem_read >> 5.001479927 S0-D1 1 4831936 Bytes llc_misses.mem_read >> 5.001479927 S1-D0 1 895104 Bytes llc_misses.mem_read >> 5.001479927 S1-D1 1 5496640 Bytes llc_misses.mem_read >> >> From above output, we can see S0-D1 and S1-D1 don't report the interval >> values, they are continued to grow. That's because check_per_pkg() wrongly >> decides to use zero counts for S0-D1 and S1-D1. >> >> So in check_per_pkg(), we should use a pair of die_id + socket_id to >> decide if this cpu counts needs to skip. Only considering socket_id is >> not enough. >> >> Now with this patch, >> >> root@lkp-csl-2ap4 ~# ./perf stat -a -I 1000 -e llc_misses.mem_read --per-die -- sleep 5 >> 1.001622560 S0-D0 1 1210176 Bytes llc_misses.mem_read >> 1.001622560 S0-D1 1 950208 Bytes llc_misses.mem_read >> 1.001622560 S1-D0 1 968704 Bytes llc_misses.mem_read >> 1.001622560 S1-D1 1 1113280 Bytes llc_misses.mem_read >> 2.004399430 S0-D0 1 1258560 Bytes llc_misses.mem_read >> 2.004399430 S0-D1 1 1011008 Bytes llc_misses.mem_read >> 2.004399430 S1-D0 1 1036544 Bytes llc_misses.mem_read >> 2.004399430 S1-D1 1 1237376 Bytes llc_misses.mem_read >> 3.006535657 S0-D0 1 1036608 Bytes llc_misses.mem_read >> 3.006535657 S0-D1 1 906560 Bytes llc_misses.mem_read >> 3.006535657 S1-D0 1 994112 Bytes llc_misses.mem_read >> 3.006535657 S1-D1 1 1025472 Bytes llc_misses.mem_read >> 4.008934402 S0-D0 1 1005120 Bytes llc_misses.mem_read >> 4.008934402 S0-D1 1 882368 Bytes llc_misses.mem_read >> 4.008934402 S1-D0 1 961408 Bytes llc_misses.mem_read >> 4.008934402 S1-D1 1 988352 Bytes llc_misses.mem_read >> 5.001605406 S0-D0 1 1930240 Bytes llc_misses.mem_read >> 5.001605406 S0-D1 1 1134272 Bytes llc_misses.mem_read >> 5.001605406 S1-D0 1 1531136 Bytes llc_misses.mem_read >> 5.001605406 S1-D1 1 2230848 Bytes llc_misses.mem_read >> >> On no-die system, die_id is 0, this patch keeps original behavior unchanged. >> >> Reported-by: Huang Ying <ying.huang@intel.com> >> Signed-off-by: Jin Yao <yao.jin@linux.intel.com> >> --- >> tools/perf/util/cpumap.h | 2 ++ >> tools/perf/util/stat.c | 21 +++++++++++++++++---- >> 2 files changed, 19 insertions(+), 4 deletions(-) >> >> diff --git a/tools/perf/util/cpumap.h b/tools/perf/util/cpumap.h >> index 3a442f021468..58604c047121 100644 >> --- a/tools/perf/util/cpumap.h >> +++ b/tools/perf/util/cpumap.h >> @@ -7,6 +7,8 @@ >> #include <internal/cpumap.h> >> #include <perf/cpumap.h> >> >> +#define CPU_MAP_MAX_DIE 256 >> + >> struct perf_record_cpu_map_data; >> >> struct perf_cpu_map *perf_cpu_map__empty_new(int nr); >> diff --git a/tools/perf/util/stat.c b/tools/perf/util/stat.c >> index 1e125e39ff84..b3fc6e261fe0 100644 >> --- a/tools/perf/util/stat.c >> +++ b/tools/perf/util/stat.c >> @@ -282,9 +282,9 @@ static void zero_per_pkg(struct evsel *counter) >> static int check_per_pkg(struct evsel *counter, >> struct perf_counts_values *vals, int cpu, bool *skip) >> { >> - unsigned long *mask = counter->per_pkg_mask; >> + unsigned long *mask = counter->per_pkg_mask, *l; >> struct perf_cpu_map *cpus = evsel__cpus(counter); >> - int s; >> + int s, d; >> >> *skip = false; >> >> @@ -295,7 +295,7 @@ static int check_per_pkg(struct evsel *counter, >> return 0; >> >> if (!mask) { >> - mask = zalloc(cpu__max_cpu()); >> + mask = zalloc(cpu__max_cpu() * CPU_MAP_MAX_DIE); >> if (!mask) >> return -ENOMEM; >> >> @@ -317,7 +317,20 @@ static int check_per_pkg(struct evsel *counter, >> if (s < 0) >> return -1; >> >> - *skip = test_and_set_bit(s, mask) == 1; >> + d = cpu_map__get_die(cpus, cpu, NULL); >> + if (d < 0) >> + return -1; >> + >> + /* >> + * On multi-die system, die_id < 256. We use a pair >> + * of socket + die to identify the used bit. >> + * On no-die system, die_id is 0, l = &mask[0]. It doesn't >> + * change original "test_and_set_bit(s, mask)" behavior. >> + */ >> + d &= 0xff; >> + l = &mask[d]; > > James is fixing the aggregation, because we could get large socket numbers: > https://lore.kernel.org/lkml/20201126141328.6509-1-james.clark@arm.com/ >
James is using "struct cpu_aggr_map" to replace "struct perf_cpu_map", but do we also need to replace the "struct perf_cpu_map" in "struct perf_evsel"? Otherwise the evsel->cpus will be inconsistent, right?
struct perf_evsel { ... struct perf_cpu_map *cpus; struct perf_cpu_map *own_cpus; ... };
> I think we should fix that in here as well
Yes, we need to fix that in check_per_pkg() as well. As I said above, in check_per_pkg(),
struct perf_cpu_map *cpus = evsel__cpus(counter);
we should use "struct cpu_aggr_map" here.
> maybe just use hashmap (socket,die) -> bool ? >
Yes, hashmap should be better, saving more memory.
Thanks Jin Yao
> jirka > >> + >> + *skip = test_and_set_bit(s, l) == 1; >> return 0; >> } >> >> -- >> 2.17.1 >> >
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