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From: Yang Jihong <yangjihong1@huawei.com>
To: Ian Rogers <irogers@google.com>
Cc: Ian Rogers <irogers@google.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Jiri Olsa <jolsa@kernel.org>, Namhyung Kim <namhyung@kernel.org>,
	Adrian Hunter <adrian.hunter@intel.com>,
	Nick Terrell <terrelln@fb.com>,
	Kan Liang <kan.liang@linux.intel.com>,
	Andi Kleen <ak@linux.intel.com>, Leo Yan <leo.yan@linaro.org>,
	Song Liu <song@kernel.org>, Sandipan Das <sandipan.das@amd.com>,
	James Clark <james.clark@arm.com>,
	Anshuman Khandual <anshuman.khandual@arm.com>,
	Miguel Ojeda <ojeda@kernel.org>,
	Liam Howlett <liam.howlett@oracle.com>,
	Athira Rajeev <atrajeev@linux.vnet.ibm.com>,
	Kajol Jain <kjain@linux.ibm.com>,
	K Prateek Nayak <kprateek.nayak@amd.com>,
	Sean Christopherson <seanjc@google.com>,
	Yanteng Si <siyanteng@loongson.cn>,
	Ravi Bangoria <ravi.bangoria@amd.com>,
	German Gomez <german.gomez@arm.com>,
	Changbin Du <changbin.du@huawei.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	liuwenyu <liuwenyu7@huawei.com>, <linux-kernel@vger.kernel.org>,
	<linux-perf-users@vger.kernel.org>
Subject: Re: [PATCH v3 20/50] perf record: Be lazier in allocating lost samples buffer
Date: Wed, 25 Oct 2023 11:44:19 +0800	[thread overview]
Message-ID: <7516348d-fe6d-9768-049e-328cfcda89ee@huawei.com> (raw)
In-Reply-To: <20231024222353.3024098-21-irogers@google.com>

Hello,

On 2023/10/25 6:23, Ian Rogers wrote:
> Wait until a lost sample occurs to allocate the lost samples buffer,
> often the buffer isn't necessary. This saves a 64kb allocation and
> 5.3kb of peak memory consumption.
> 
> Signed-off-by: Ian Rogers <irogers@google.com>
> ---
>   tools/perf/builtin-record.c | 29 +++++++++++++++++++----------
>   1 file changed, 19 insertions(+), 10 deletions(-)
> 
> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> index 9b4f3805ca92..b6c8c1371b39 100644
> --- a/tools/perf/builtin-record.c
> +++ b/tools/perf/builtin-record.c
> @@ -1924,21 +1924,13 @@ static void __record__save_lost_samples(struct record *rec, struct evsel *evsel,
>   static void record__read_lost_samples(struct record *rec)
>   {
>   	struct perf_session *session = rec->session;
> -	struct perf_record_lost_samples *lost;
> +	struct perf_record_lost_samples *lost = NULL;
>   	struct evsel *evsel;
>   
>   	/* there was an error during record__open */
>   	if (session->evlist == NULL)
>   		return;
>   
> -	lost = zalloc(PERF_SAMPLE_MAX_SIZE);
> -	if (lost == NULL) {
> -		pr_debug("Memory allocation failed\n");
> -		return;
> -	}
> -
> -	lost->header.type = PERF_RECORD_LOST_SAMPLES;
> -
>   	evlist__for_each_entry(session->evlist, evsel) {
>   		struct xyarray *xy = evsel->core.sample_id;
>   		u64 lost_count;
> @@ -1961,6 +1953,14 @@ static void record__read_lost_samples(struct record *rec)
>   				}
>   
>   				if (count.lost) {
> +					if (!lost) {
> +						lost = zalloc(PERF_SAMPLE_MAX_SIZE);
> +						if (!lost) {
> +							pr_debug("Memory allocation failed\n");
> +							return;
> +						}
> +						lost->header.type = PERF_RECORD_LOST_SAMPLES;
> +					}
>   					__record__save_lost_samples(rec, evsel, lost,
>   								    x, y, count.lost, 0);
>   				}
> @@ -1968,9 +1968,18 @@ static void record__read_lost_samples(struct record *rec)
>   		}
>   
>   		lost_count = perf_bpf_filter__lost_count(evsel);
> -		if (lost_count)
> +		if (lost_count) {
> +			if (!lost) {
> +				lost = zalloc(PERF_SAMPLE_MAX_SIZE);
> +				if (!lost) {
> +					pr_debug("Memory allocation failed\n");
> +					return;
> +				}
> +				lost->header.type = PERF_RECORD_LOST_SAMPLES;
> +			}
>   			__record__save_lost_samples(rec, evsel, lost, 0, 0, lost_count,
>   						    PERF_RECORD_MISC_LOST_SAMPLES_BPF);
> +		}
>   	}

Can zalloc for `lost` be moved to __record__save_lost_samples?
This simplifies the code.


diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index dcf288a4fb9a..8d2eb746031a 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -1888,14 +1888,25 @@ record__switch_output(struct record *rec, bool 
at_exit)
  }

  static void __record__save_lost_samples(struct record *rec, struct 
evsel *evsel,
-                                       struct perf_record_lost_samples 
*lost,
+                                       struct perf_record_lost_samples 
**plost,
                                         int cpu_idx, int thread_idx, 
u64 lost_count,
                                         u16 misc_flag)
  {
         struct perf_sample_id *sid;
         struct perf_sample sample = {};
+       struct perf_record_lost_samples *lost = *plost;
         int id_hdr_size;

+       if (!lost) {
+               lost = zalloc(PERF_SAMPLE_MAX_SIZE);
+               if (!lost) {
+                       pr_debug("Memory allocation failed\n");
+                       return;
+               }
+               lost->header.type = PERF_RECORD_LOST_SAMPLES;
+               *plost = lost;
+       }
+
         lost->lost = lost_count;
         if (evsel->core.ids) {
                 sid = xyarray__entry(evsel->core.sample_id, cpu_idx, 
thread_idx);
@@ -1912,21 +1923,13 @@ static void __record__save_lost_samples(struct 
record *rec, struct evsel *evsel,
  static void record__read_lost_samples(struct record *rec)
  {
         struct perf_session *session = rec->session;
-       struct perf_record_lost_samples *lost;
+       struct perf_record_lost_samples *lost = NULL;
         struct evsel *evsel;

         /* there was an error during record__open */
         if (session->evlist == NULL)
                 return;

-       lost = zalloc(PERF_SAMPLE_MAX_SIZE);
-       if (lost == NULL) {
-               pr_debug("Memory allocation failed\n");
-               return;
-       }
-
-       lost->header.type = PERF_RECORD_LOST_SAMPLES;
-
         evlist__for_each_entry(session->evlist, evsel) {
                 struct xyarray *xy = evsel->core.sample_id;
                 u64 lost_count;
@@ -1949,7 +1952,7 @@ static void record__read_lost_samples(struct 
record *rec)
                                 }

                                 if (count.lost) {
-                                       __record__save_lost_samples(rec, 
evsel, lost,
+                                       __record__save_lost_samples(rec, 
evsel, &lost,
                                                                     x, 
y, count.lost, 0);
                                 }
                         }
@@ -1957,11 +1960,12 @@ static void record__read_lost_samples(struct 
record *rec)

                 lost_count = perf_bpf_filter__lost_count(evsel);
                 if (lost_count)
-                       __record__save_lost_samples(rec, evsel, lost, 0, 
0, lost_count,
+                       __record__save_lost_samples(rec, evsel, &lost, 
0, 0, lost_count,
 
PERF_RECORD_MISC_LOST_SAMPLES_BPF);
         }
  out:
-       free(lost);
+       if (lost)
+               free(lost);
  }

  static volatile sig_atomic_t workload_exec_errno;


Thanks,
Yang

  reply	other threads:[~2023-10-25  3:45 UTC|newest]

Thread overview: 62+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-10-24 22:23 [PATCH v3 00/50] Improvements to memory use Ian Rogers
2023-10-24 22:23 ` [PATCH v3 01/50] perf rwsem: Add debug mode that uses a mutex Ian Rogers
2023-10-24 22:23 ` [PATCH v3 02/50] perf machine: Avoid out of bounds LBR memory read Ian Rogers
2023-10-24 22:23 ` [PATCH v3 03/50] libperf rc_check: Make implicit enabling work for GCC Ian Rogers
2023-10-24 22:23 ` [PATCH v3 04/50] libperf rc_check: Add RC_CHK_EQUAL Ian Rogers
2023-10-24 22:23 ` [PATCH v3 05/50] perf hist: Add missing puts to hist__account_cycles Ian Rogers
2023-10-24 22:23 ` [PATCH v3 06/50] perf threads: Remove unused dead thread list Ian Rogers
2023-10-24 22:23 ` [PATCH v3 07/50] perf offcpu: Add missed btf_free Ian Rogers
2023-10-24 22:23 ` [PATCH v3 08/50] perf callchain: Make display use of branch_type_stat const Ian Rogers
2023-10-24 22:23 ` [PATCH v3 09/50] perf callchain: Make brtype_stat in callchain_list optional Ian Rogers
2023-10-24 22:23 ` [PATCH v3 10/50] perf callchain: Minor layout changes to callchain_list Ian Rogers
2023-10-24 22:23 ` [PATCH v3 11/50] perf mem_info: Add and use map_symbol__exit and addr_map_symbol__exit Ian Rogers
2023-10-24 22:23 ` [PATCH v3 12/50] perf record: Lazy load kernel symbols Ian Rogers
2023-10-25 18:25   ` Namhyung Kim
2023-10-25 18:35     ` Adrian Hunter
2023-10-24 22:23 ` [PATCH v3 13/50] libperf: Lazily allocate mmap event copy Ian Rogers
2023-10-25  2:38   ` Yang Jihong
2023-10-25  3:28     ` Ian Rogers
2023-10-24 22:23 ` [PATCH v3 14/50] perf mmap: Lazily initialize zstd streams Ian Rogers
2023-10-24 22:23 ` [PATCH v3 15/50] perf machine thread: Remove exited threads by default Ian Rogers
2023-10-24 22:23 ` [PATCH v3 16/50] tools api fs: Switch filename__read_str to use io.h Ian Rogers
2023-10-24 22:23 ` [PATCH v3 17/50] tools api fs: Avoid reading whole file for a 1 byte bool Ian Rogers
2023-10-24 22:23 ` [PATCH v3 18/50] tools lib api: Add io_dir an allocation free readdir alternative Ian Rogers
2023-10-25 18:43   ` Namhyung Kim
2023-10-25 22:15     ` Ian Rogers
2023-10-24 22:23 ` [PATCH v3 19/50] perf maps: Switch modules tree walk to io_dir__readdir Ian Rogers
2023-10-24 22:23 ` [PATCH v3 20/50] perf record: Be lazier in allocating lost samples buffer Ian Rogers
2023-10-25  3:44   ` Yang Jihong [this message]
2023-10-25 17:00     ` Ian Rogers
2023-10-25 19:04       ` Namhyung Kim
2023-10-25 19:00   ` Namhyung Kim
2023-10-24 22:23 ` [PATCH v3 21/50] perf pmu: Switch to io_dir__readdir Ian Rogers
2023-10-24 22:23 ` [PATCH v3 22/50] perf bpf: Don't synthesize BPF events when disabled Ian Rogers
2023-10-24 22:23 ` [PATCH v3 23/50] perf header: Switch mem topology to io_dir__readdir Ian Rogers
2023-10-24 22:23 ` [PATCH v3 24/50] perf events: Remove scandir in thread synthesis Ian Rogers
2023-10-24 22:23 ` [PATCH v3 25/50] perf map: Simplify map_ip/unmap_ip and make map size smaller Ian Rogers
2023-10-24 22:23 ` [PATCH v3 26/50] perf maps: Move symbol maps functions to maps.c Ian Rogers
2023-10-24 22:23 ` [PATCH v3 27/50] perf thread: Add missing RC_CHK_ACCESS Ian Rogers
2023-10-24 22:23 ` [PATCH v3 28/50] perf maps: Add maps__for_each_map to call a function on each entry Ian Rogers
2023-10-24 22:23 ` [PATCH v3 29/50] perf maps: Add remove maps function to remove a map based on callback Ian Rogers
2023-10-24 22:23 ` [PATCH v3 30/50] perf debug: Expose debug file Ian Rogers
2023-10-24 22:23 ` [PATCH v3 31/50] perf maps: Refactor maps__fixup_overlappings Ian Rogers
2023-10-24 22:23 ` [PATCH v3 32/50] perf maps: Do simple merge if given map doesn't overlap Ian Rogers
2023-10-24 22:23 ` [PATCH v3 33/50] perf maps: Rename clone to copy from Ian Rogers
2023-10-24 22:23 ` [PATCH v3 34/50] perf maps: Add maps__load_first Ian Rogers
2023-10-24 22:23 ` [PATCH v3 35/50] perf maps: Add find next entry to give entry after the given map Ian Rogers
2023-10-24 22:23 ` [PATCH v3 36/50] perf maps: Reduce scope of map_rb_node and maps internals Ian Rogers
2023-10-24 22:23 ` [PATCH v3 37/50] perf maps: Fix up overlaps during fixup_end Ian Rogers
2023-10-24 22:23 ` [PATCH v3 38/50] perf maps: Switch from rbtree to lazily sorted array for addresses Ian Rogers
2023-10-24 22:23 ` [PATCH v3 39/50] perf maps: Get map before returning in maps__find Ian Rogers
2023-10-24 22:23 ` [PATCH v3 40/50] perf maps: Get map before returning in maps__find_by_name Ian Rogers
2023-10-24 22:23 ` [PATCH v3 41/50] perf maps: Get map before returning in maps__find_next_entry Ian Rogers
2023-10-24 22:23 ` [PATCH v3 42/50] perf maps: Hide maps internals Ian Rogers
2023-10-24 22:23 ` [PATCH v3 43/50] perf maps: Locking tidy up of nr_maps Ian Rogers
2023-10-24 22:23 ` [PATCH v3 44/50] perf dso: Reorder variables to save space in struct dso Ian Rogers
2023-10-24 22:23 ` [PATCH v3 45/50] perf report: Sort child tasks by tid Ian Rogers
2023-10-24 22:23 ` [PATCH v3 46/50] perf trace: Ignore thread hashing in summary Ian Rogers
2023-10-24 22:23 ` [PATCH v3 47/50] perf machine: Move fprintf to for_each loop and a callback Ian Rogers
2023-10-24 22:23 ` [PATCH v3 48/50] perf threads: Move threads to its own files Ian Rogers
2023-10-24 22:23 ` [PATCH v3 49/50] perf threads: Switch from rbtree to hashmap Ian Rogers
2023-10-24 22:23 ` [PATCH v3 50/50] perf threads: Reduce table size from 256 to 8 Ian Rogers
2023-10-26 17:11 ` (subset) [PATCH v3 00/50] Improvements to memory use Namhyung Kim

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