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From: Ian Rogers <irogers@google.com>
To: andi@firstfloor.org
Cc: acme@kernel.org, ak@kernel.org, ak@linux.intel.com,
	 linux-perf-users@vger.kernel.org, namhyung@kernel.org,
	 Ian Rogers <irogers@google.com>
Subject: [PATCH v1 5/7] perf Documentation: Add tip for hybrid event merging
Date: Sun, 23 Aug 2026 23:37:42 -0700	[thread overview]
Message-ID: <20260824063744.1533837-6-irogers@google.com> (raw)
In-Reply-To: <20260824063744.1533837-1-irogers@google.com>

Add informative text outlining the IPC imbalances associated with
merging cross-hybrid core events like cycles.

Signed-off-by: Ian Rogers <irogers@google.com>
Assisted-by: Antigravity:gemini-3.1-pro
---
 tools/perf/Documentation/tips.txt | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/perf/Documentation/tips.txt b/tools/perf/Documentation/tips.txt
index ebf12a8c5db5..1c7b309fe6e8 100644
--- a/tools/perf/Documentation/tips.txt
+++ b/tools/perf/Documentation/tips.txt
@@ -66,3 +66,4 @@ For latency profiling, try: perf record/report --latency
 For parallelism histogram, try: perf report --hierarchy --sort latency,parallelism,comm,symbol
 To analyze particular parallelism levels, try: perf report --latency --parallelism=32-64
 To see how parallelism changes over time, try: perf report -F time,latency,parallelism --time-quantum=1s
+When merging events like cycles, different core frequencies and instructions per cycle mean the counts may not fairly reflect time spent in a function.
-- 
2.55.0.766.g2966f0265a-goog


  parent reply	other threads:[~2026-08-24  6:38 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-08-13 13:25 [PATCH v1] perf top: Merge hybrid common events Andi Kleen
2026-08-13 13:57 ` sashiko-bot
2026-08-17 19:40 ` Ian Rogers
2026-08-18 17:29   ` Andi Kleen
2026-08-19  2:58     ` Ian Rogers
2026-08-19  3:34       ` Andi Kleen
2026-08-19  4:16         ` Ian Rogers
2026-08-19 16:11           ` Andi Kleen
2026-08-19 17:58             ` Ian Rogers
2026-08-19 18:25               ` Andi Kleen
2026-08-19 22:18                 ` Ian Rogers
2026-08-24  6:37 ` [PATCH v1 0/7] perf ui: Implement hybrid event merging for heterogeneous systems Ian Rogers
2026-08-24  6:37   ` [PATCH v1 1/7] perf evlist: Implement evlist__can_merge_hybrid using first_wildcard_match Ian Rogers
2026-08-24  6:53     ` sashiko-bot
2026-08-24 22:49     ` Andi Kleen
2026-08-25  4:01       ` Ian Rogers
2026-08-24  6:37   ` [PATCH v1 2/7] perf ui hist: Add support for aggregated total_period and merging entries cleanly Ian Rogers
2026-08-24  6:53     ` sashiko-bot
2026-08-24  6:37   ` [PATCH v1 3/7] perf ui browsers: Implement interactive 'M' keystroke to toggle hybrid event merging Ian Rogers
2026-08-24  6:49     ` sashiko-bot
2026-08-24  6:37   ` [PATCH v1 4/7] perf tools: Expose opt-in --hybrid-merge Ian Rogers
2026-08-24  6:52     ` sashiko-bot
2026-08-24 22:40     ` Andi Kleen
2026-08-25  3:33       ` Ian Rogers
2026-08-25 22:19         ` Arnaldo Carvalho de Melo
2026-08-24  6:37   ` Ian Rogers [this message]
2026-08-24  6:40     ` [PATCH v1 5/7] perf Documentation: Add tip for hybrid event merging sashiko-bot
2026-08-24  6:37   ` [PATCH v1 6/7] perf ui hist: Format group headers iteratively based on proportional visual allocations Ian Rogers
2026-08-24  6:53     ` sashiko-bot
2026-08-24  6:37   ` [PATCH v1 7/7] perf test: Expand top tests for --hybrid-merge Ian Rogers
2026-08-24  6:55     ` sashiko-bot

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