tools/perf/scripts/python/flamegraph.py | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-)
When processing the perf data file generated with multiple events,
the flamegraph script will count all the events regardless of
different event names. If specify the perf data file with -i option,
the script will try to read the header information regardless of
the file name specified, instead it will try to access the perf.data.
This patch tries to add a -e option to specify the event name that
the flamegraph will be generated accordingly. If the -e option omitted,
the behavior remains unchanged. If the -i option specified, the header
information will be read from that file.
Signed-off-by: Tianyou Li <tianyou.li@intel.com>
Reviewed-by: Pan Deng <pan.deng@intel.com>
Reviewed-by: Zhiguo Zhou <zhiguo.zhou@intel.com>
Reviewed-by: Wangyang Guo <wangyang.guo@intel.com>
Reviewed-by: Tim Chen <tim.c.chen@linux.intel.com>
---
tools/perf/scripts/python/flamegraph.py | 21 +++++++++++++++++++--
1 file changed, 19 insertions(+), 2 deletions(-)
diff --git a/tools/perf/scripts/python/flamegraph.py b/tools/perf/scripts/python/flamegraph.py
index cf7ce8229a..eb78b93925 100755
--- a/tools/perf/scripts/python/flamegraph.py
+++ b/tools/perf/scripts/python/flamegraph.py
@@ -94,6 +94,11 @@ class FlameGraphCLI:
return child
def process_event(self, event):
+ # ignore events where the event name does not match
+ # the one specified by the user
+ if self.args.event_name and event.get("ev_name") != self.args.event_name:
+ return
+
pid = event.get("sample", {}).get("pid", 0)
# event["dso"] sometimes contains /usr/lib/debug/lib/modules/*/vmlinux
# for user-space processes; let's use pid for kernel or user-space distinction
@@ -123,8 +128,15 @@ class FlameGraphCLI:
return ""
try:
- output = subprocess.check_output(["perf", "report", "--header-only"])
- return output.decode("utf-8")
+ if self.args.input:
+ output = subprocess.check_output(["perf", "script", "--header-only", "-i", self.args.input])
+ else:
+ output = subprocess.check_output(["perf", "report", "--header-only"])
+
+ result = output.decode("utf-8")
+ if self.args.event_name:
+ result += "\nFocused event: " + self.args.event_name
+ return result
except Exception as err: # pylint: disable=broad-except
print("Error reading report header: {}".format(err), file=sys.stderr)
return ""
@@ -235,6 +247,11 @@ if __name__ == "__main__":
default=False,
action="store_true",
help="allow unprompted downloading of HTML template")
+ parser.add_argument("-e", "--event",
+ default="",
+ dest="event_name",
+ type=str,
+ help="specify the event to generate flamegraph for")
cli_args = parser.parse_args()
cli = FlameGraphCLI(cli_args)
--
2.43.5Hello,
On Tue, Jun 03, 2025 at 03:10:48PM +0800, Tianyou Li wrote:
> When processing the perf data file generated with multiple events,
> the flamegraph script will count all the events regardless of
> different event names. If specify the perf data file with -i option,
> the script will try to read the header information regardless of
> the file name specified, instead it will try to access the perf.data.
>
> This patch tries to add a -e option to specify the event name that
> the flamegraph will be generated accordingly. If the -e option omitted,
> the behavior remains unchanged. If the -i option specified, the header
> information will be read from that file.
Looks like two separate changes. Can you please split them?
Thanks,
Namhyung
>
> Signed-off-by: Tianyou Li <tianyou.li@intel.com>
> Reviewed-by: Pan Deng <pan.deng@intel.com>
> Reviewed-by: Zhiguo Zhou <zhiguo.zhou@intel.com>
> Reviewed-by: Wangyang Guo <wangyang.guo@intel.com>
> Reviewed-by: Tim Chen <tim.c.chen@linux.intel.com>
> ---
> tools/perf/scripts/python/flamegraph.py | 21 +++++++++++++++++++--
> 1 file changed, 19 insertions(+), 2 deletions(-)
>
> diff --git a/tools/perf/scripts/python/flamegraph.py b/tools/perf/scripts/python/flamegraph.py
> index cf7ce8229a..eb78b93925 100755
> --- a/tools/perf/scripts/python/flamegraph.py
> +++ b/tools/perf/scripts/python/flamegraph.py
> @@ -94,6 +94,11 @@ class FlameGraphCLI:
> return child
>
> def process_event(self, event):
> + # ignore events where the event name does not match
> + # the one specified by the user
> + if self.args.event_name and event.get("ev_name") != self.args.event_name:
> + return
> +
> pid = event.get("sample", {}).get("pid", 0)
> # event["dso"] sometimes contains /usr/lib/debug/lib/modules/*/vmlinux
> # for user-space processes; let's use pid for kernel or user-space distinction
> @@ -123,8 +128,15 @@ class FlameGraphCLI:
> return ""
>
> try:
> - output = subprocess.check_output(["perf", "report", "--header-only"])
> - return output.decode("utf-8")
> + if self.args.input:
> + output = subprocess.check_output(["perf", "script", "--header-only", "-i", self.args.input])
> + else:
> + output = subprocess.check_output(["perf", "report", "--header-only"])
> +
> + result = output.decode("utf-8")
> + if self.args.event_name:
> + result += "\nFocused event: " + self.args.event_name
> + return result
> except Exception as err: # pylint: disable=broad-except
> print("Error reading report header: {}".format(err), file=sys.stderr)
> return ""
> @@ -235,6 +247,11 @@ if __name__ == "__main__":
> default=False,
> action="store_true",
> help="allow unprompted downloading of HTML template")
> + parser.add_argument("-e", "--event",
> + default="",
> + dest="event_name",
> + type=str,
> + help="specify the event to generate flamegraph for")
>
> cli_args = parser.parse_args()
> cli = FlameGraphCLI(cli_args)
> --
> 2.43.5
>
Hi Namhyung,
Thanks for your review and suggestions. I have split the patch into two patches. Please let me know if anything else is needed. Thanks.
Regards,
Tianyou
-----Original Message-----
From: Namhyung Kim <namhyung@kernel.org>
Sent: Tuesday, June 10, 2025 9:20 AM
To: Li, Tianyou <tianyou.li@intel.com>
Cc: 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>; Ian Rogers <irogers@google.com>; Hunter, Adrian <adrian.hunter@intel.com>; Kan Liang <kan.liang@linux.intel.com>; Guo, Wangyang <wangyang.guo@intel.com>; Deng, Pan <pan.deng@intel.com>; Zhou, Zhiguo <zhiguo.zhou@intel.com>; Chen, Tim C <tim.c.chen@intel.com>; tim.c.chen@linux.intel.com; linux-perf-users@vger.kernel.org; linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Minor improvements for perf script flamegraph
Hello,
On Tue, Jun 03, 2025 at 03:10:48PM +0800, Tianyou Li wrote:
> When processing the perf data file generated with multiple events, the
> flamegraph script will count all the events regardless of different
> event names. If specify the perf data file with -i option, the script
> will try to read the header information regardless of the file name
> specified, instead it will try to access the perf.data.
>
> This patch tries to add a -e option to specify the event name that the
> flamegraph will be generated accordingly. If the -e option omitted,
> the behavior remains unchanged. If the -i option specified, the header
> information will be read from that file.
Looks like two separate changes. Can you please split them?
Thanks,
Namhyung
>
> Signed-off-by: Tianyou Li <tianyou.li@intel.com>
> Reviewed-by: Pan Deng <pan.deng@intel.com>
> Reviewed-by: Zhiguo Zhou <zhiguo.zhou@intel.com>
> Reviewed-by: Wangyang Guo <wangyang.guo@intel.com>
> Reviewed-by: Tim Chen <tim.c.chen@linux.intel.com>
> ---
> tools/perf/scripts/python/flamegraph.py | 21 +++++++++++++++++++--
> 1 file changed, 19 insertions(+), 2 deletions(-)
>
> diff --git a/tools/perf/scripts/python/flamegraph.py
> b/tools/perf/scripts/python/flamegraph.py
> index cf7ce8229a..eb78b93925 100755
> --- a/tools/perf/scripts/python/flamegraph.py
> +++ b/tools/perf/scripts/python/flamegraph.py
> @@ -94,6 +94,11 @@ class FlameGraphCLI:
> return child
>
> def process_event(self, event):
> + # ignore events where the event name does not match
> + # the one specified by the user
> + if self.args.event_name and event.get("ev_name") != self.args.event_name:
> + return
> +
> pid = event.get("sample", {}).get("pid", 0)
> # event["dso"] sometimes contains /usr/lib/debug/lib/modules/*/vmlinux
> # for user-space processes; let's use pid for kernel or
> user-space distinction @@ -123,8 +128,15 @@ class FlameGraphCLI:
> return ""
>
> try:
> - output = subprocess.check_output(["perf", "report", "--header-only"])
> - return output.decode("utf-8")
> + if self.args.input:
> + output = subprocess.check_output(["perf", "script", "--header-only", "-i", self.args.input])
> + else:
> + output = subprocess.check_output(["perf", "report",
> + "--header-only"])
> +
> + result = output.decode("utf-8")
> + if self.args.event_name:
> + result += "\nFocused event: " + self.args.event_name
> + return result
> except Exception as err: # pylint: disable=broad-except
> print("Error reading report header: {}".format(err), file=sys.stderr)
> return ""
> @@ -235,6 +247,11 @@ if __name__ == "__main__":
> default=False,
> action="store_true",
> help="allow unprompted downloading of HTML
> template")
> + parser.add_argument("-e", "--event",
> + default="",
> + dest="event_name",
> + type=str,
> + help="specify the event to generate
> + flamegraph for")
>
> cli_args = parser.parse_args()
> cli = FlameGraphCLI(cli_args)
> --
> 2.43.5
>
© 2016 - 2026 Red Hat, Inc.