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Date:   Thu, 24 Dec 2020 10:26:05 -0300
From:   Arnaldo Carvalho de Melo <acme@...nel.org>
To:     Jin Yao <yao.jin@...ux.intel.com>
Cc:     James Clark <james.clark@....com>,
        John Garry <john.garry@...wei.com>,
        Jiri Olsa <jolsa@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...nel.org>,
        alexander.shishkin@...ux.intel.com, Linux-kernel@...r.kernel.org,
        ak@...ux.intel.com, kan.liang@...el.com, yao.jin@...el.com,
        ying.huang@...el.com
Subject: Re: [PATCH v2] perf stat: Fix wrong skipping for per-die aggregation

Em Thu, Dec 24, 2020 at 08:54:04PM +0800, Jin Yao escreveu:
> 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

So, I applied a series that refactors the perf stat aggregation code and
your patch albeit applying cleanly, doesn't compile:

  CC       /tmp/build/perf/util/topdown.o
util/stat.c: In function ‘check_per_pkg’:
util/stat.c:348:6: error: incompatible types when assigning to type ‘int’ from type ‘struct aggr_cpu_id’
  348 |  d = cpu_map__get_die(cpus, cpu, NULL);
      |      ^~~~~~~~~~~~~~~~
make[4]: *** [/home/acme/git/perf/tools/build/Makefile.build:97: /tmp/build/perf/util/stat.o] Error 1
make[4]: *** Waiting for unfinished jobs....


I'm still testing this to push publicly to my perf/core branch, but I'll
push now to tmp.perf/core and you can go from there, ok?

This is what you should find there, just pushed:

8d4852b468c38168 (HEAD -> perf/core, five/perf/core) perf stat aggregation: Add separate thread member
b993381779da406c perf stat aggregation: Add separate core member
ba2ee166d92b2010 perf stat aggregation: Add separate die member
1a270cb6b3cc1866 perf stat aggregation: Add separate socket member
fcd83a35dd93b89d perf stat aggregation: Add separate node member
ff5232956e074994 perf stat aggregation: Start using cpu_aggr_id in map
d526e1a033e03ec4 perf cpumap: Drop in cpu_aggr_map struct
cea6575fdccfc062 perf cpumap: Add new map type for aggregation
2760f5a14fe7aa46 perf stat: Replace aggregation ID with a struct
fa265e59b81a09fa perf cpumap: Add new struct for cpu aggregation
91585846f105ef2e perf cpumap: Use existing allocator to avoid using malloc
23331eeb731a503a perf tests: Improve topology test to check all aggregation types
b27d20ab1c6a1a77 perf tools: Update s390's syscall.tbl copy from the kernel sources
c5ef52944a2d8001 perf tools: Update powerpc's syscall.tbl copy from the kernel sources
22ffc3f5598d2a51 perf s390: Move syscall.tbl check into check-headers.sh
[acme@...co perf]$

- Arnaldo
 
> 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@...-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 hashmap(socket,die) to decide if
> the cpu counts needs to skip. Only considering socket is not enough.
> 
> Now with this patch,
> 
> root@...-csl-2ap4 ~# ./perf stat -a -I 1000 -e llc_misses.mem_read --per-die -- sleep 5
>      1.001617187 S0-D0           1             952768 Bytes llc_misses.mem_read
>      1.001617187 S0-D1           1             849152 Bytes llc_misses.mem_read
>      1.001617187 S1-D0           1             854912 Bytes llc_misses.mem_read
>      1.001617187 S1-D1           1             948672 Bytes llc_misses.mem_read
>      2.004138021 S0-D0           1            1200256 Bytes llc_misses.mem_read
>      2.004138021 S0-D1           1             899840 Bytes llc_misses.mem_read
>      2.004138021 S1-D0           1             898752 Bytes llc_misses.mem_read
>      2.004138021 S1-D1           1            1039424 Bytes llc_misses.mem_read
>      3.006463971 S0-D0           1            1029056 Bytes llc_misses.mem_read
>      3.006463971 S0-D1           1             894336 Bytes llc_misses.mem_read
>      3.006463971 S1-D0           1             905088 Bytes llc_misses.mem_read
>      3.006463971 S1-D1           1            1042880 Bytes llc_misses.mem_read
>      4.008831441 S0-D0           1             920576 Bytes llc_misses.mem_read
>      4.008831441 S0-D1           1             877248 Bytes llc_misses.mem_read
>      4.008831441 S1-D0           1             883968 Bytes llc_misses.mem_read
>      4.008831441 S1-D1           1             967168 Bytes llc_misses.mem_read
>      5.001441349 S0-D0           1             864704 Bytes llc_misses.mem_read
>      5.001441349 S0-D1           1             827456 Bytes llc_misses.mem_read
>      5.001441349 S1-D0           1             829632 Bytes llc_misses.mem_read
>      5.001441349 S1-D1           1             925760 Bytes llc_misses.mem_read
> 
> On no-die system, die_id is 0, actually it's hashmap(socket,0), original behavior
> is not changed.
> 
> Reported-by: Huang Ying <ying.huang@...el.com>
> Signed-off-by: Jin Yao <yao.jin@...ux.intel.com>
> ---
>  tools/perf/util/evsel.c |  4 ++-
>  tools/perf/util/evsel.h |  3 +-
>  tools/perf/util/stat.c  | 61 +++++++++++++++++++++++++++++++++++++----
>  3 files changed, 60 insertions(+), 8 deletions(-)
> 
> diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
> index c26ea82220bd..9715ed9b03f6 100644
> --- a/tools/perf/util/evsel.c
> +++ b/tools/perf/util/evsel.c
> @@ -45,6 +45,7 @@
>  #include "string2.h"
>  #include "memswap.h"
>  #include "util.h"
> +#include "hashmap.h"
>  #include "../perf-sys.h"
>  #include "util/parse-branch-options.h"
>  #include <internal/xyarray.h>
> @@ -1377,7 +1378,8 @@ void evsel__exit(struct evsel *evsel)
>  	zfree(&evsel->group_name);
>  	zfree(&evsel->name);
>  	zfree(&evsel->pmu_name);
> -	zfree(&evsel->per_pkg_mask);
> +	hashmap__free(evsel->per_pkg_mask);
> +	evsel->per_pkg_mask = NULL;
>  	zfree(&evsel->metric_events);
>  	perf_evsel__object.fini(evsel);
>  }
> diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
> index cd1d8dd43199..951628943fd0 100644
> --- a/tools/perf/util/evsel.h
> +++ b/tools/perf/util/evsel.h
> @@ -17,6 +17,7 @@ struct cgroup;
>  struct perf_counts;
>  struct perf_stat_evsel;
>  union perf_event;
> +struct hashmap;
>  
>  typedef int (evsel__sb_cb_t)(union perf_event *event, void *data);
>  
> @@ -110,7 +111,7 @@ struct evsel {
>  	bool			merged_stat;
>  	bool			reset_group;
>  	bool			errored;
> -	unsigned long		*per_pkg_mask;
> +	struct hashmap		*per_pkg_mask;
>  	struct evsel		*leader;
>  	struct list_head	config_terms;
>  	int			err;
> diff --git a/tools/perf/util/stat.c b/tools/perf/util/stat.c
> index 1e125e39ff84..15db4bda1266 100644
> --- a/tools/perf/util/stat.c
> +++ b/tools/perf/util/stat.c
> @@ -13,6 +13,7 @@
>  #include "evlist.h"
>  #include "evsel.h"
>  #include "thread_map.h"
> +#include "hashmap.h"
>  #include <linux/zalloc.h>
>  
>  void update_stats(struct stats *stats, u64 val)
> @@ -275,16 +276,39 @@ void evlist__save_aggr_prev_raw_counts(struct evlist *evlist)
>  
>  static void zero_per_pkg(struct evsel *counter)
>  {
> -	if (counter->per_pkg_mask)
> -		memset(counter->per_pkg_mask, 0, cpu__max_cpu());
> +	struct hashmap_entry *entry;
> +	size_t bkt;
> +
> +	if (counter->per_pkg_mask) {
> +		hashmap__for_each_entry(counter->per_pkg_mask, entry, bkt) {
> +			bool *used = (bool *)entry->value;
> +
> +			*used = false;
> +		}
> +	}
> +}
> +
> +static size_t id_hash(const void *key, void *ctx __maybe_unused)
> +{
> +	int socket = (int64_t)key >> 32;
> +
> +	return socket;
> +}
> +
> +static bool id_equal(const void *key1, const void *key2,
> +		     void *ctx __maybe_unused)
> +{
> +	return (int64_t)key1 == (int64_t)key2;
>  }
>  
>  static int check_per_pkg(struct evsel *counter,
>  			 struct perf_counts_values *vals, int cpu, bool *skip)
>  {
> -	unsigned long *mask = counter->per_pkg_mask;
> +	struct hashmap *mask = counter->per_pkg_mask;
>  	struct perf_cpu_map *cpus = evsel__cpus(counter);
> -	int s;
> +	int s, d, ret;
> +	uint64_t key;
> +	bool *used;
>  
>  	*skip = false;
>  
> @@ -295,7 +319,7 @@ static int check_per_pkg(struct evsel *counter,
>  		return 0;
>  
>  	if (!mask) {
> -		mask = zalloc(cpu__max_cpu());
> +		mask = hashmap__new(id_hash, id_equal, NULL);
>  		if (!mask)
>  			return -ENOMEM;
>  
> @@ -317,7 +341,32 @@ static int check_per_pkg(struct evsel *counter,
>  	if (s < 0)
>  		return -1;
>  
> -	*skip = test_and_set_bit(s, mask) == 1;
> +	/*
> +	 * On multi-die system, 0 < die_id < 256. On no-die system, die_id = 0.
> +	 * We use hashmap(socket, die) to check the used socket+die pair.
> +	 */
> +	d = cpu_map__get_die(cpus, cpu, NULL);
> +	if (d < 0)
> +		return -1;
> +
> +	key = (uint64_t)s << 32 | (d & 0xff);
> +	if (hashmap__find(mask, (void *)key, (void **)&used)) {
> +		if (*used)
> +			*skip = true;
> +		*used = true;
> +	} else {
> +		used = zalloc(sizeof(*used));
> +		if (!used)
> +			return -1;
> +
> +		*used = true;
> +		ret = hashmap__add(mask, (void *)key, used);
> +		if (ret) {
> +			free(used);
> +			return -1;
> +		}
> +	}
> +
>  	return 0;
>  }
>  
> -- 
> 2.17.1
> 

-- 

- Arnaldo

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