From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5707B481248; Wed, 3 Jun 2026 19:21:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780514505; cv=none; b=J9B5SLSu1/VxftLnNz3VgpKGrSAhF8lhz9puPbWR9ynOeh4UvfQDb07DNMwOGYDqV/5Dgm+XYh4/tvb6F4IzMznlHdLf9qObliT6jZZ9vTfaCxuSFuTdlxL1V08m3SGyB/NWtc3ObY6Fdl8cS18Ruwx5vvhws5fkdjabseqTwYo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780514505; c=relaxed/simple; bh=lb8Z5BjDrTa2yy5/cYk1wUZGDvnAZCM4gkw7mbKqBGk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=ap68x4v+V6ynex+cECPgA25HKl1OrQ5eUYTRBwHEZ1P5HhlOc/Ts3lOtwa5fZptmfLtnWMQs/QD6tlQUHaRnNUY8djs7e0RcMXzXZQvWvC27y4pJ1Xs03CoZm+kXnfCbfJWGTDYig5C2pG5oDSiOpbTDuAzVg2raEhtdaw2UTTg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=nRi/bsXd; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="nRi/bsXd" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 524B41F00893; Wed, 3 Jun 2026 19:21:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1780514504; bh=GOQrXSl4xXPviDTu6jc900ukeDv1QAv2FTmczDd1Eyg=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=nRi/bsXdChw5GPtf78tSKyX1XL2bRl/yMacTaxWmV/4rCVhwBWXHOyCxwUCqp5lZd XU9dn23pYbR3qpN0GVreFO093uwzDu8WzrQDgBze7NbtEcTqsjh5ymnlaD2SD9UkQe NvucyIJeTQKPpZCYiUGZLBq/GjzPAVQO1hzlYSEPm/POWD0IA+H06djM7HqWL4tAxH E2jOzgDFv4BWUuWkRZf5ybZZ5XpNnh0FbE33Q6Q6AQq0Kv7oV1kFrBSFY3luvqDIEe yRWwQKcb7gNAmNRpM+BJcWzUql4iIZkvISXEFU1Ua68pwXLxLnXJ+qjIMkJAvOwVZk ZHXJdTes3M9aA== Date: Wed, 3 Jun 2026 16:21:39 -0300 From: Arnaldo Carvalho de Melo To: James Clark Cc: Suzuki K Poulose , Mike Leach , Leo Yan , Namhyung Kim , Jiri Olsa , Ian Rogers , Amir Ayupov , Jonathan Corbet , Shuah Khan , Paschalis Mpeis , coresight@lists.linaro.org, linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, Arnaldo Carvalho de Melo , linux-doc@vger.kernel.org Subject: Re: [PATCH v2 02/18] perf test: Add workload-ctl option Message-ID: References: <20260602-james-cs-context-tracking-fix-v2-0-85b5ce6f55c6@linaro.org> <20260602-james-cs-context-tracking-fix-v2-2-85b5ce6f55c6@linaro.org> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260602-james-cs-context-tracking-fix-v2-2-85b5ce6f55c6@linaro.org> On Tue, Jun 02, 2026 at 03:26:44PM +0100, James Clark wrote: > Add a --workload-ctl=fifo:ctl-fifo[,ack-fifo] option for 'perf test > -w'. When set, run_workload() opens the named FIFO, writes enable before > invoking the builtin workload, writes disable before returning, and > waits for ack responses when an ack FIFO is provided to ensure that the > workload doesn't run until the events are enabled. > > This can be used to limit the scope of the recording to only the > workload execution and avoid recording Perf setup and teardown code if > Perf record is started with events disabled (-D 1). I see no mention to the equivalent in 'perf record', from its man page: ---------------------------------------------------------------------- --control=fifo:ctl-fifo[,ack-fifo]:: --control=fd:ctl-fd[,ack-fd]:: ctl-fifo / ack-fifo are opened and used as ctl-fd / ack-fd as follows. Listen on ctl-fd descriptor for command to control measurement. Available commands: - 'enable' : enable events - 'disable' : disable events - 'enable name' : enable event 'name' - 'disable name' : disable event 'name' - 'snapshot' : AUX area tracing snapshot). - 'stop' : stop perf record - 'ping' : ping - 'evlist [-v|-g|-F] : display all events -F Show just the sample frequency used for each event. -v Show all fields. -g Show event group information. ---------------------------------------------------------------------- Can this be shared code? - Arnaldo > Assisted-by: Codex:GPT-5.5 > Signed-off-by: James Clark > --- > tools/perf/Documentation/perf-test.txt | 6 ++ > tools/perf/tests/builtin-test.c | 184 ++++++++++++++++++++++++++++++++- > 2 files changed, 188 insertions(+), 2 deletions(-) > > diff --git a/tools/perf/Documentation/perf-test.txt b/tools/perf/Documentation/perf-test.txt > index 32da0d1fa86a..1faf30d4a7be 100644 > --- a/tools/perf/Documentation/perf-test.txt > +++ b/tools/perf/Documentation/perf-test.txt > @@ -69,3 +69,9 @@ OPTIONS > > --list-workloads:: > List the available workloads to use with -w/--workload. > + > +--workload-ctl=fifo:ctl-fifo[,ack-fifo]:: > + Write 'enable' to ctl-fifo before running the workload and 'disable' > + before returning. If ack-fifo is provided, the workload runner waits for > + an 'ack' response after each command. This scopes the recording to only > + the workload if used with 'perf record -D 1 --control ...'. > diff --git a/tools/perf/tests/builtin-test.c b/tools/perf/tests/builtin-test.c > index f2c135891477..d5df3efdce3b 100644 > --- a/tools/perf/tests/builtin-test.c > +++ b/tools/perf/tests/builtin-test.c > @@ -50,6 +50,7 @@ static bool sequential; > static unsigned int runs_per_test = 1; > const char *dso_to_test; > const char *test_objdump_path = "objdump"; > +static const char *workload_control; > > /* > * List of architecture specific tests. Not a weak symbol as the array length is > @@ -161,6 +162,11 @@ static struct test_workload *workloads[] = { > #endif > }; > > +struct workload_control { > + int ctl_fd; > + int ack_fd; > +}; > + > #define workloads__for_each(workload) \ > for (unsigned i = 0; i < ARRAY_SIZE(workloads) && ({ workload = workloads[i]; 1; }); i++) > > @@ -711,13 +717,185 @@ static int workloads__fprintf_list(FILE *fp) > return printed; > } > > +static int perf_control_open_fifo(struct workload_control *ctl, const char *str) > +{ > + char *s, *p; > + int ret; > + > + if (strncmp(str, "fifo:", 5)) > + return -EINVAL; > + > + str += 5; > + if (!*str || *str == ',') > + return -EINVAL; > + > + s = strdup(str); > + if (!s) > + return -ENOMEM; > + > + p = strchr(s, ','); > + if (p) > + *p = '\0'; > + > + ctl->ctl_fd = open(s, O_WRONLY | O_CLOEXEC); > + if (ctl->ctl_fd < 0) { > + ret = -errno; > + pr_err("Failed to open workload control FIFO '%s': %m\n", s); > + free(s); > + return ret; > + } > + > + if (p && *++p) { > + ctl->ack_fd = open(p, O_RDONLY | O_CLOEXEC); > + if (ctl->ack_fd < 0) { > + ret = -errno; > + pr_err("Failed to open workload control ack FIFO '%s': %m\n", p); > + close(ctl->ctl_fd); > + ctl->ctl_fd = -1; > + free(s); > + return ret; > + } > + } > + > + free(s); > + return 0; > +} > + > +static int perf_control_open(struct workload_control *ctl) > +{ > + int ret; > + > + if (!workload_control) > + return 0; > + > + ret = perf_control_open_fifo(ctl, workload_control); > + > + if (ret == -EINVAL) { > + pr_err("Unsupported workload control spec '%s', expected fifo:ctl-fifo[,ack-fifo]\n", > + workload_control); > + } > + > + return ret; > +} > + > +static void perf_control_close(struct workload_control *ctl) > +{ > + if (ctl->ctl_fd >= 0) { > + close(ctl->ctl_fd); > + ctl->ctl_fd = -1; > + } > + if (ctl->ack_fd >= 0) { > + close(ctl->ack_fd); > + ctl->ack_fd = -1; > + } > +} > + > +static int perf_control_write_cmd(int fd, const char *cmd) > +{ > + size_t len = strlen(cmd); > + ssize_t ret; > + > + while (len) { > + ret = write(fd, cmd, len); > + if (ret < 0) { > + if (errno == EINTR) > + continue; > + pr_err("Failed to write perf control command '%s': %m\n", cmd); > + return -1; > + } > + > + if (!ret) { > + pr_err("Failed to write perf control command '%s': short write\n", cmd); > + return -1; > + } > + > + cmd += ret; > + len -= ret; > + } > + > + return 0; > +} > + > +static int perf_control_read_ack(int fd) > +{ > + char buf[16]; > + ssize_t ret; > + > + do { > + ret = read(fd, buf, sizeof(buf) - 1); > + } while (ret < 0 && errno == EINTR); > + > + if (ret < 0) { > + pr_err("Failed to read perf control ack: %m\n"); > + return -1; > + } > + > + if (!ret) { > + pr_err("Unexpected EOF while reading perf control ack\n"); > + return -1; > + } > + > + buf[ret] = '\0'; > + for (ssize_t i = 0; i < ret; i++) { > + if (buf[i] == '\n' || buf[i] == '\0') { > + buf[i] = '\0'; > + break; > + } > + } > + > + if (strcmp(buf, "ack")) { > + pr_err("Unexpected perf control ack: %s\n", buf); > + return -1; > + } > + > + return 0; > +} > + > +static int perf_control_send(struct workload_control *ctl, const char *cmd) > +{ > + if (ctl->ctl_fd < 0) > + return 0; > + > + if (perf_control_write_cmd(ctl->ctl_fd, cmd)) > + return -1; > + > + if (ctl->ack_fd >= 0 && perf_control_read_ack(ctl->ack_fd)) > + return -1; > + > + return 0; > +} > + > static int run_workload(const char *work, int argc, const char **argv) > { > struct test_workload *twl; > > workloads__for_each(twl) { > - if (!strcmp(twl->name, work)) > - return twl->func(argc, argv); > + struct workload_control ctl = { > + .ctl_fd = -1, > + .ack_fd = -1, > + }; > + int control_ret, ret; > + > + if (strcmp(twl->name, work)) > + continue; > + > + ret = perf_control_open(&ctl); > + if (ret) > + return ret; > + > + if (perf_control_send(&ctl, "enable\n")) { > + perf_control_close(&ctl); > + return -1; > + } > + > + ret = twl->func(argc, argv); > + > + control_ret = perf_control_send(&ctl, "disable\n"); > + perf_control_close(&ctl); > + if (control_ret) > + return -1; > + > + return ret; > } > > pr_info("No workload found: %s\n", work); > @@ -799,6 +977,8 @@ int cmd_test(int argc, const char **argv) > OPT_UINTEGER('r', "runs-per-test", &runs_per_test, > "Run each test the given number of times, default 1"), > OPT_STRING('w', "workload", &workload, "work", "workload to run for testing, use '--list-workloads' to list the available ones."), > + OPT_STRING(0, "workload-ctl", &workload_control, "fifo:ctl-fifo[,ack-fifo]", > + "Write enable to the fifo just before running the workload and disable after, with optional ack from ack-fifo"), > OPT_BOOLEAN(0, "list-workloads", &list_workloads, "List the available builtin workloads to use with -w/--workload"), > OPT_STRING(0, "dso", &dso_to_test, "dso", "dso to test"), > OPT_STRING(0, "objdump", &test_objdump_path, "path", > > -- > 2.34.1