[PATCH v2 2/3] rtla: fix -C/--cgroup interface
From: Ivan Pravdin <hidden>
Date: 2025-08-12 17:21:57
Also in:
linux-doc, lkml
Subsystem:
documentation, real-time linux analysis (rtla) tools, the rest · Maintainers:
Jonathan Corbet, Steven Rostedt, Tomas Glozar, Linus Torvalds
Currently, user can only specify cgroup to the tracer's thread the
following ways:
`-C[cgroup]`
`-C[=cgroup]`
`--cgroup[=cgroup]`
If user tries to specify cgroup as `-C [cgroup]` or `--cgroup [cgroup]`,
the parser silently fails and rtla's cgroup is used for the tracer
threads.
To make interface more user-friendly, allow user to specify cgroup in
the aforementioned way, i.e. `-C [cgroup]` and `--cgroup [cgroup]`
Change documentation to reflect this user interface change.
Fixes: a957cbc02531 ("rtla: Add -C cgroup support")
Signed-off-by: Ivan Pravdin <redacted>
---
Documentation/tools/rtla/common_options.rst | 2 +-
tools/tracing/rtla/src/osnoise_hist.c | 17 +++++++++++------
tools/tracing/rtla/src/osnoise_top.c | 17 +++++++++++------
tools/tracing/rtla/src/timerlat_hist.c | 17 +++++++++++------
tools/tracing/rtla/src/timerlat_top.c | 17 +++++++++++------
5 files changed, 45 insertions(+), 25 deletions(-)
diff --git a/Documentation/tools/rtla/common_options.rst b/Documentation/tools/rtla/common_options.rst
index 2dc1575210aa..3f292a12b7af 100644
--- a/Documentation/tools/rtla/common_options.rst
+++ b/Documentation/tools/rtla/common_options.rst@@ -42,7 +42,7 @@ - *f:prio* - use SCHED_FIFO with *prio*; - *d:runtime[us|ms|s]:period[us|ms|s]* - use SCHED_DEADLINE with *runtime* and *period* in nanoseconds. -**-C**, **--cgroup**\[*=cgroup*] +**-C**, **--cgroup** \[*cgroup*] Set a *cgroup* to the tracer's threads. If the **-C** option is passed without arguments, the tracer's thread will inherit **rtla**'s *cgroup*. Otherwise, the threads will be placed on the *cgroup* passed to the option.
diff --git a/tools/tracing/rtla/src/osnoise_hist.c b/tools/tracing/rtla/src/osnoise_hist.c
index 8d579bcee709..298640d92434 100644
--- a/tools/tracing/rtla/src/osnoise_hist.c
+++ b/tools/tracing/rtla/src/osnoise_hist.c@@ -435,7 +435,7 @@ static void osnoise_hist_usage(char *usage) " -T/--threshold us: the minimum delta to be considered a noise", " -c/--cpus cpu-list: list of cpus to run osnoise threads", " -H/--house-keeping cpus: run rtla control threads only on the given cpus", - " -C/--cgroup[=cgroup_name]: set cgroup, if no cgroup_name is passed, the rtla's cgroup will be inherited", + " -C/--cgroup [cgroup_name]: set cgroup, if no cgroup_name is passed, the rtla's cgroup will be inherited", " -d/--duration time[s|m|h|d]: duration of the session", " -D/--debug: print debug info", " -t/--trace[file]: save the stopped trace to [file|osnoise_trace.txt]",
@@ -559,12 +559,17 @@ static struct osnoise_params break; case 'C': params->cgroup = 1; - if (!optarg) { - /* will inherit this cgroup */ + if (optarg) { + if (optarg[0] == '=') { + /* skip the = */ + params->cgroup_name = &optarg[1]; + } else { + params->cgroup_name = optarg; + } + } else if (optind < argc && argv[optind][0] != '-') { + params->cgroup_name = argv[optind]; + } else { params->cgroup_name = NULL; - } else if (*optarg == '=') { - /* skip the = */ - params->cgroup_name = ++optarg; } break; case 'D':
diff --git a/tools/tracing/rtla/src/osnoise_top.c b/tools/tracing/rtla/src/osnoise_top.c
index 2c12780c8aa9..70924242bcdd 100644
--- a/tools/tracing/rtla/src/osnoise_top.c
+++ b/tools/tracing/rtla/src/osnoise_top.c@@ -269,7 +269,7 @@ static void osnoise_top_usage(struct osnoise_params *params, char *usage) " -T/--threshold us: the minimum delta to be considered a noise", " -c/--cpus cpu-list: list of cpus to run osnoise threads", " -H/--house-keeping cpus: run rtla control threads only on the given cpus", - " -C/--cgroup[=cgroup_name]: set cgroup, if no cgroup_name is passed, the rtla's cgroup will be inherited", + " -C/--cgroup [cgroup_name]: set cgroup, if no cgroup_name is passed, the rtla's cgroup will be inherited", " -d/--duration time[s|m|h|d]: duration of the session", " -D/--debug: print debug info", " -t/--trace[file]: save the stopped trace to [file|osnoise_trace.txt]",
@@ -394,12 +394,17 @@ struct osnoise_params *osnoise_top_parse_args(int argc, char **argv) break; case 'C': params->cgroup = 1; - if (!optarg) { - /* will inherit this cgroup */ + if (optarg) { + if (optarg[0] == '=') { + /* skip the = */ + params->cgroup_name = &optarg[1]; + } else { + params->cgroup_name = optarg; + } + } else if (optind < argc && argv[optind][0] != '-') { + params->cgroup_name = argv[optind]; + } else { params->cgroup_name = NULL; - } else if (*optarg == '=') { - /* skip the = */ - params->cgroup_name = ++optarg; } break; case 'D':
diff --git a/tools/tracing/rtla/src/timerlat_hist.c b/tools/tracing/rtla/src/timerlat_hist.c
index 9baea1b251ed..2a48a076d941 100644
--- a/tools/tracing/rtla/src/timerlat_hist.c
+++ b/tools/tracing/rtla/src/timerlat_hist.c@@ -726,7 +726,7 @@ static void timerlat_hist_usage(char *usage) " -s/--stack us: save the stack trace at the IRQ if a thread latency is higher than the argument in us", " -c/--cpus cpus: run the tracer only on the given cpus", " -H/--house-keeping cpus: run rtla control threads only on the given cpus", - " -C/--cgroup[=cgroup_name]: set cgroup, if no cgroup_name is passed, the rtla's cgroup will be inherited", + " -C/--cgroup [cgroup_name]: set cgroup, if no cgroup_name is passed, the rtla's cgroup will be inherited", " -d/--duration time[m|h|d]: duration of the session in seconds", " --dump-tasks: prints the task running on all CPUs if stop conditions are met (depends on !--no-aa)", " -D/--debug: print debug info",
@@ -885,12 +885,17 @@ static struct timerlat_params break; case 'C': params->cgroup = 1; - if (!optarg) { - /* will inherit this cgroup */ + if (optarg) { + if (optarg[0] == '=') { + /* skip the = */ + params->cgroup_name = &optarg[1]; + } else { + params->cgroup_name = optarg; + } + } else if (optind < argc && argv[optind][0] != '-') { + params->cgroup_name = argv[optind]; + } else { params->cgroup_name = NULL; - } else if (*optarg == '=') { - /* skip the = */ - params->cgroup_name = ++optarg; } break; case 'b':
diff --git a/tools/tracing/rtla/src/timerlat_top.c b/tools/tracing/rtla/src/timerlat_top.c
index c80b81c0b4da..e45d9978744c 100644
--- a/tools/tracing/rtla/src/timerlat_top.c
+++ b/tools/tracing/rtla/src/timerlat_top.c@@ -492,7 +492,7 @@ static void timerlat_top_usage(char *usage) " -s/--stack us: save the stack trace at the IRQ if a thread latency is higher than the argument in us", " -c/--cpus cpus: run the tracer only on the given cpus", " -H/--house-keeping cpus: run rtla control threads only on the given cpus", - " -C/--cgroup[=cgroup_name]: set cgroup, if no cgroup_name is passed, the rtla's cgroup will be inherited", + " -C/--cgroup [cgroup_name]: set cgroup, if no cgroup_name is passed, the rtla's cgroup will be inherited", " -d/--duration time[s|m|h|d]: duration of the session", " -D/--debug: print debug info", " --dump-tasks: prints the task running on all CPUs if stop conditions are met (depends on !--no-aa)",
@@ -650,12 +650,17 @@ static struct timerlat_params break; case 'C': params->cgroup = 1; - if (!optarg) { - /* will inherit this cgroup */ + if (optarg) { + if (optarg[0] == '=') { + /* skip the = */ + params->cgroup_name = &optarg[1]; + } else { + params->cgroup_name = optarg; + } + } else if (optind < argc && argv[optind][0] != '-') { + params->cgroup_name = argv[optind]; + } else { params->cgroup_name = NULL; - } else if (*optarg == '=') { - /* skip the = */ - params->cgroup_name = ++optarg; } break; case 'D':
--
2.48.1