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charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20240724-perf_set_event_limit-v1-2-e680c93eca55@rivosinc.com> References: <20240724-perf_set_event_limit-v1-0-e680c93eca55@rivosinc.com> In-Reply-To: <20240724-perf_set_event_limit-v1-0-e680c93eca55@rivosinc.com> To: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Mark Rutland , Alexander Shishkin , Jiri Olsa , Ian Rogers , Adrian Hunter , Atish Patra Cc: linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, Charlie Jenkins X-Mailer: b4 0.13.0 X-Developer-Signature: v=1; a=ed25519-sha256; t=1721861667; l=886; i=charlie@rivosinc.com; s=20231120; h=from:subject:message-id; bh=4M35RJ0MrhFzvtO/gpzcZAZGyvkPqgVAOXcftDMuvps=; b=Ft1lYHdZdmWJU19FBYN1LMTLSqpqK9Wblkotv6+rB4MEMMnCzwlA1VGTJPEZ6Ma4ZEXBf2s4b gWs9Eg58Rr4AyJkOjYV2FmoT85V2BsuXM+5lI0uCnMS6HfFmTK5vsvq X-Developer-Key: i=charlie@rivosinc.com; a=ed25519; pk=t4RSWpMV1q5lf/NWIeR9z58bcje60/dbtxxmoSfBEcs= Introduce PERF_EVENT_IOC_SET_EVENT_LIMIT and explain the differences between it and PERF_EVENT_IOC_REFRESH. Signed-off-by: Charlie Jenkins --- tools/perf/design.txt | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/tools/perf/design.txt b/tools/perf/design.txt index aa8cfeabb743..1626ae83785a 100644 --- a/tools/perf/design.txt +++ b/tools/perf/design.txt @@ -439,6 +439,11 @@ Additionally, non-inherited overflow counters can use =20 to enable a counter for 'nr' events, after which it gets disabled again. =20 +PERF_EVENT_IOC_REFRESH will increment the event limit by 'nr' and enable t= he +event. To increment the event limit without enabling it, use the following: + + ioctl(fd, PERF_EVENT_IOC_INC_EVENT_LIMIT, nr); + A process can enable or disable all the counter groups that are attached to it, using prctl: =20 --=20 2.44.0