From: Tomas Glozar <tglozar(a)redhat.com>
When using rtla timerlat with userspace threads (-u or -U), rtla
disables the OSNOISE_WORKLOAD option in
/sys/kernel/tracing/osnoise/options. This option is not re-enabled in a
subsequent run with kernel-space threads, leading to rtla collecting no
results if the previous run exited abnormally:
$ rtla timerlat top -u
^\Quit (core dumped)
$ rtla timerlat top -k -d 1s
Timer Latency
0 00:00:01 | IRQ Timer Latency (us) | Thread Timer Latency (us)
CPU COUNT | cur min avg max | cur min avg max
The issue persists until OSNOISE_WORKLOAD is set manually by running:
$ echo OSNOISE_WORKLOAD > /sys/kernel/tracing/osnoise/options
Set OSNOISE_WORKLOAD when running rtla with kernel-space threads if
available to fix the issue.
Cc: stable(a)vger.kernel.org
Cc: John Kacur <jkacur(a)redhat.com>
Cc: Luis Goncalves <lgoncalv(a)redhat.com>
Link: https://lore.kernel.org/20250107144823.239782-4-tglozar@redhat.com
Fixes: cdca4f4e5e8e ("rtla/timerlat_top: Add timerlat user-space support")
Signed-off-by: Tomas Glozar <tglozar(a)redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt(a)goodmis.org>
---
tools/tracing/rtla/src/timerlat_top.c | 15 +++++++++------
1 file changed, 9 insertions(+), 6 deletions(-)
diff --git a/tools/tracing/rtla/src/timerlat_top.c b/tools/tracing/rtla/src/timerlat_top.c
index d358cd39f360..f387597d3ac2 100644
--- a/tools/tracing/rtla/src/timerlat_top.c
+++ b/tools/tracing/rtla/src/timerlat_top.c
@@ -851,12 +851,15 @@ timerlat_top_apply_config(struct osnoise_tool *top, struct timerlat_top_params *
}
}
- if (params->user_top) {
- retval = osnoise_set_workload(top->context, 0);
- if (retval) {
- err_msg("Failed to set OSNOISE_WORKLOAD option\n");
- goto out_err;
- }
+ /*
+ * Set workload according to type of thread if the kernel supports it.
+ * On kernels without support, user threads will have already failed
+ * on missing timerlat_fd, and kernel threads do not need it.
+ */
+ retval = osnoise_set_workload(top->context, params->kernel_workload);
+ if (retval < -1) {
+ err_msg("Failed to set OSNOISE_WORKLOAD option\n");
+ goto out_err;
}
if (isatty(STDOUT_FILENO) && !params->quiet)
--
2.45.2
From: Tomas Glozar <tglozar(a)redhat.com>
When using rtla timerlat with userspace threads (-u or -U), rtla
disables the OSNOISE_WORKLOAD option in
/sys/kernel/tracing/osnoise/options. This option is not re-enabled in a
subsequent run with kernel-space threads, leading to rtla collecting no
results if the previous run exited abnormally:
$ rtla timerlat hist -u
^\Quit (core dumped)
$ rtla timerlat hist -k -d 1s
Index
over:
count:
min:
avg:
max:
ALL: IRQ Thr Usr
count: 0 0 0
min: - - -
avg: - - -
max: - - -
The issue persists until OSNOISE_WORKLOAD is set manually by running:
$ echo OSNOISE_WORKLOAD > /sys/kernel/tracing/osnoise/options
Set OSNOISE_WORKLOAD when running rtla with kernel-space threads if
available to fix the issue.
Cc: stable(a)vger.kernel.org
Cc: John Kacur <jkacur(a)redhat.com>
Cc: Luis Goncalves <lgoncalv(a)redhat.com>
Link: https://lore.kernel.org/20250107144823.239782-3-tglozar@redhat.com
Fixes: ed774f7481fa ("rtla/timerlat_hist: Add timerlat user-space support")
Signed-off-by: Tomas Glozar <tglozar(a)redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt(a)goodmis.org>
---
tools/tracing/rtla/src/timerlat_hist.c | 15 +++++++++------
1 file changed, 9 insertions(+), 6 deletions(-)
diff --git a/tools/tracing/rtla/src/timerlat_hist.c b/tools/tracing/rtla/src/timerlat_hist.c
index 53ded187b33a..d4bd02c01c53 100644
--- a/tools/tracing/rtla/src/timerlat_hist.c
+++ b/tools/tracing/rtla/src/timerlat_hist.c
@@ -1085,12 +1085,15 @@ timerlat_hist_apply_config(struct osnoise_tool *tool, struct timerlat_hist_param
}
}
- if (params->user_hist) {
- retval = osnoise_set_workload(tool->context, 0);
- if (retval) {
- err_msg("Failed to set OSNOISE_WORKLOAD option\n");
- goto out_err;
- }
+ /*
+ * Set workload according to type of thread if the kernel supports it.
+ * On kernels without support, user threads will have already failed
+ * on missing timerlat_fd, and kernel threads do not need it.
+ */
+ retval = osnoise_set_workload(tool->context, params->kernel_workload);
+ if (retval < -1) {
+ err_msg("Failed to set OSNOISE_WORKLOAD option\n");
+ goto out_err;
}
return 0;
--
2.45.2