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Message-ID: <20250610005742.2173050-1-namhyung@kernel.org>
Date: Mon, 9 Jun 2025 17:57:42 -0700
From: Namhyung Kim <namhyung@...nel.org>
To: Arnaldo Carvalho de Melo <acme@...nel.org>,
Ian Rogers <irogers@...gle.com>,
Kan Liang <kan.liang@...ux.intel.com>
Cc: Jiri Olsa <jolsa@...nel.org>,
Adrian Hunter <adrian.hunter@...el.com>,
Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...nel.org>,
LKML <linux-kernel@...r.kernel.org>,
linux-perf-users@...r.kernel.org,
Ravi Bangoria <ravi.bangoria@....com>
Subject: [PATCH for-v6.16] perf mem: Describe the new output fields in the doc
Update the documentation of the new fields with examples and caveats.
Also update the related documentation for AMD IBS.
Cc: Ravi Bangoria <ravi.bangoria@....com>
Signed-off-by: Namhyung Kim <namhyung@...nel.org>
---
tools/perf/Documentation/perf-amd-ibs.txt | 59 ++++++++++++++++-------
tools/perf/Documentation/perf-mem.txt | 50 +++++++++++++++++++
2 files changed, 92 insertions(+), 17 deletions(-)
diff --git a/tools/perf/Documentation/perf-amd-ibs.txt b/tools/perf/Documentation/perf-amd-ibs.txt
index 55f80beae0375a72..54854993576070c3 100644
--- a/tools/perf/Documentation/perf-amd-ibs.txt
+++ b/tools/perf/Documentation/perf-amd-ibs.txt
@@ -171,23 +171,48 @@ Below is a simple example of the perf mem tool.
# perf mem report
A normal perf mem report output will provide detailed memory access profile.
-However, it can also be aggregated based on output fields. For example:
-
- # perf mem report -F mem,sample,snoop
- Samples: 3M of event 'ibs_op//', Event count (approx.): 23524876
- Memory access Samples Snoop
- N/A 1903343 N/A
- L1 hit 1056754 N/A
- L2 hit 75231 N/A
- L3 hit 9496 HitM
- L3 hit 2270 N/A
- RAM hit 8710 N/A
- Remote node, same socket RAM hit 3241 N/A
- Remote core, same node Any cache hit 1572 HitM
- Remote core, same node Any cache hit 514 N/A
- Remote node, same socket Any cache hit 1216 HitM
- Remote node, same socket Any cache hit 350 N/A
- Uncached hit 18 N/A
+New output fields will show related access info together. For example:
+
+ # perf mem report -F overhead,cache,snoop,comm
+ ...
+ # Samples: 92K of event 'ibs_op//'
+ # Total weight : 531104
+ #
+ # ---------- Cache ----------- --- Snoop ----
+ # Overhead L1 L2 L1-buf Other HitM Other Command
+ # ........ ............................ .............. ..........
+ #
+ 76.07% 5.8% 35.7% 0.0% 34.6% 23.3% 52.8% cc1
+ 5.79% 0.2% 0.0% 0.0% 5.6% 0.1% 5.7% make
+ 5.78% 0.1% 4.4% 0.0% 1.2% 0.5% 5.3% gcc
+ 5.33% 0.3% 3.9% 0.0% 1.1% 0.2% 5.2% as
+ 5.00% 0.1% 3.8% 0.0% 1.0% 0.3% 4.7% sh
+ 1.56% 0.1% 0.1% 0.0% 1.4% 0.6% 0.9% ld
+ 0.28% 0.1% 0.0% 0.0% 0.2% 0.1% 0.2% pkg-config
+ 0.09% 0.0% 0.0% 0.0% 0.1% 0.0% 0.1% git
+ 0.03% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% rm
+ ...
+
+Also, it can be aggregated based on various memory access info using the
+sort keys. For example:
+
+ # perf mem report -s mem,snoop
+ ...
+ # Samples: 92K of event 'ibs_op//'
+ # Total weight : 531104
+ # Sort order : mem,snoop
+ #
+ # Overhead Samples Memory access Snoop
+ # ........ ............ ....................................... ............
+ #
+ 47.99% 1509 L2 hit N/A
+ 25.08% 338 core, same node Any cache hit HitM
+ 10.24% 54374 N/A N/A
+ 6.77% 35938 L1 hit N/A
+ 6.39% 101 core, same node Any cache hit N/A
+ 3.50% 69 RAM hit N/A
+ 0.03% 158 LFB/MAB hit N/A
+ 0.00% 2 Uncached hit N/A
Please refer to their man page for more detail.
diff --git a/tools/perf/Documentation/perf-mem.txt b/tools/perf/Documentation/perf-mem.txt
index 965e73d377724607..4d164836d0943119 100644
--- a/tools/perf/Documentation/perf-mem.txt
+++ b/tools/perf/Documentation/perf-mem.txt
@@ -119,6 +119,22 @@ REPORT OPTIONS
And the default sort keys are changed to local_weight, mem, sym, dso,
symbol_daddr, dso_daddr, snoop, tlb, locked, blocked, local_ins_lat.
+-F::
+--fields=::
+ Specify output field - multiple keys can be specified in CSV format.
+ Please see linkperf:perf-report[1] for details.
+
+ In addition to the default fields, 'perf mem report' will provide the
+ following fields to break down sample periods.
+
+ - op: operation in the sample instruction (load, store, prefetch, ...)
+ - cache: location in CPU cache (L1, L2, ...) where the sample hit
+ - mem: location in memory or other places the sample hit
+ - dtlb: location in Data TLB (L1, L2) where the sample hit
+ - snoop: snoop result for the sampled data access
+
+ Please take a look at the OUTPUT FIELD SELECTION section for caveats.
+
-T::
--type-profile::
Show data-type profile result instead of code symbols. This requires
@@ -156,6 +172,40 @@ there are two samples in perf.data file, both with the same sample period,
90% [k] memcpy
10% [.] strcmp
+OUTPUT FIELD SELECTION
+----------------------
+"perf mem report" adds a number of new output fields specific to data source
+information in the sample. Some of them have the same name with the existing
+sort keys ("mem" and "snoop"). So unlike other fields and sort keys, they'll
+behave differently when it's used by -F/--fields or -s/--sort.
+
+Using those two as output fields will aggregate samples altogether and show
+breakdown.
+
+ $ perf mem report -F mem,snoop
+ ...
+ # ------ Memory ------- --- Snoop ----
+ # RAM Uncach Other HitM Other
+ # ..................... ..............
+ #
+ 3.5% 0.0% 96.5% 25.1% 74.9%
+
+But using the same name for sort keys will aggregate samples for each type
+separately.
+
+ $ perf mem report -s mem,snoop
+ # Overhead Samples Memory access Snoop
+ # ........ ............ ....................................... ............
+ #
+ 47.99% 1509 L2 hit N/A
+ 25.08% 338 core, same node Any cache hit HitM
+ 10.24% 54374 N/A N/A
+ 6.77% 35938 L1 hit N/A
+ 6.39% 101 core, same node Any cache hit N/A
+ 3.50% 69 RAM hit N/A
+ 0.03% 158 LFB/MAB hit N/A
+ 0.00% 2 Uncached hit N/A
+
SEE ALSO
--------
linkperf:perf-record[1], linkperf:perf-report[1], linkperf:perf-arm-spe[1]
--
2.50.0.rc0.604.gd4ff7b7c86-goog
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