[for-next][PATCH 06/11] rtla/timerlat_hist: Add auto-analysis support

Steven Rostedt
2023-06-13T22:08:59Z

Add auto-analysis to timerlat hist, including the --no-aa option to
reduce overhead and --dump-task. --aa-only was not added as it is
already on timerlat top.

Link: https://lkml.kernel.org/r/c2693f47ee83e659a7723fed8035f5d2534f528e.1686066600.git.bristot@kernel.org

Cc: William White <chwhite@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Tested-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
.../tools/rtla/common_timerlat_aa.rst | 7 ---
.../tools/rtla/rtla-timerlat-hist.rst | 7 ++-
.../tools/rtla/rtla-timerlat-top.rst | 7 +++
tools/tracing/rtla/src/timerlat_hist.c | 51 ++++++++++++++++++-
4 files changed, 61 insertions(+), 11 deletions(-)

diff --git a/Documentation/tools/rtla/common_timerlat_aa.rst b/Documentation/tools/rtla/common_timerlat_aa.rst
index 795b9fbcbc6d..077029e6b289 100644
--- a/Documentation/tools/rtla/common_timerlat_aa.rst
+++ b/Documentation/tools/rtla/common_timerlat_aa.rst
@@ -5,10 +5,3 @@
**--no-aa**

disable auto-analysis, reducing rtla timerlat cpu usage
-
-**--aa-only** *us*
-
- Set stop tracing conditions and run without collecting and displaying statistics.
- Print the auto-analysis if the system hits the stop tracing condition. This option
- is useful to reduce rtla timerlat CPU, enabling the debug without the overhead of
- collecting the statistics.
diff --git a/Documentation/tools/rtla/rtla-timerlat-hist.rst b/Documentation/tools/rtla/rtla-timerlat-hist.rst
index 6bf7f0ca4556..057db78d4095 100644
--- a/Documentation/tools/rtla/rtla-timerlat-hist.rst
+++ b/Documentation/tools/rtla/rtla-timerlat-hist.rst
@@ -29,15 +29,18 @@ OPTIONS

.. include:: common_options.rst

+.. include:: common_timerlat_aa.rst
+
EXAMPLE
=======
In the example below, **rtla timerlat hist** is set to run for *10* minutes,
in the cpus *0-4*, *skipping zero* only lines. Moreover, **rtla timerlat
hist** will change the priority of the *timerlat* threads to run under
*SCHED_DEADLINE* priority, with a *10us* runtime every *1ms* period. The
-*1ms* period is also passed to the *timerlat* tracer::
+*1ms* period is also passed to the *timerlat* tracer. Auto-analysis is disabled
+to reduce overhead ::

- [root@alien ~]# timerlat hist -d 10m -c 0-4 -P d:100us:1ms -p 1ms
+ [root@alien ~]# timerlat hist -d 10m -c 0-4 -P d:100us:1ms -p 1ms --no-aa
# RTLA timerlat histogram
# Time unit is microseconds (us)
# Duration: 0 00:10:00
diff --git a/Documentation/tools/rtla/rtla-timerlat-top.rst b/Documentation/tools/rtla/rtla-timerlat-top.rst
index 73799c1150ad..1b7cf4e3eafe 100644
--- a/Documentation/tools/rtla/rtla-timerlat-top.rst
+++ b/Documentation/tools/rtla/rtla-timerlat-top.rst
@@ -32,6 +32,13 @@ OPTIONS

.. include:: common_timerlat_aa.rst

+**--aa-only** *us*
+
+ Set stop tracing conditions and run without collecting and displaying statistics.
+ Print the auto-analysis if the system hits the stop tracing condition. This option
+ is useful to reduce rtla timerlat CPU, enabling the debug without the overhead of
+ collecting the statistics.
+
EXAMPLE
=======

diff --git a/tools/tracing/rtla/src/timerlat_hist.c b/tools/tracing/rtla/src/timerlat_hist.c
index 1675d54cae81..e720c8908906 100644
--- a/tools/tracing/rtla/src/timerlat_hist.c
+++ b/tools/tracing/rtla/src/timerlat_hist.c
@@ -16,6 +16,7 @@
#include "utils.h"
#include "osnoise.h"
#include "timerlat.h"
+#include "timerlat_aa.h"

struct timerlat_hist_params {
char *cpus;
@@ -34,6 +35,8 @@ struct timerlat_hist_params {
int dma_latency;
int cgroup;
int hk_cpus;
+ int no_aa;
+ int dump_tasks;
cpu_set_t hk_cpu_set;
struct sched_attr sched_param;
struct trace_events *events;
@@ -438,7 +441,7 @@ static void timerlat_hist_usage(char *usage)
" usage: [rtla] timerlat hist [-h] [-q] [-d s] [-D] [-n] [-a us] [-p us] [-i us] [-T us] [-s us] \\",
" [-t[=file]] [-e sys[:event]] [--filter <filter>] [--trigger <trigger>] [-c cpu-list] [-H cpu-list]\\",
" [-P priority] [-E N] [-b N] [--no-irq] [--no-thread] [--no-header] [--no-summary] \\",
- " [--no-index] [--with-zeros] [--dma-latency us] [-C[=cgroup_name]]",
+ " [--no-index] [--with-zeros] [--dma-latency us] [-C[=cgroup_name]] [--no-aa] [--dump-task]",
"",
" -h/--help: print this menu",
" -a/--auto: set automatic trace mode, stopping the session if argument in us latency is hit",
@@ -450,12 +453,14 @@ static void timerlat_hist_usage(char *usage)
" -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",
" -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",
" -t/--trace[=file]: save the stopped trace to [file|timerlat_trace.txt]",
" -e/--event <sys:event>: enable the <sys:event> in the trace instance, multiple -e are allowed",
" --filter <filter>: enable a trace event filter to the previous -e event",
" --trigger <trigger>: enable a trace event trigger to the previous -e event",
" -n/--nano: display data in nanoseconds",
+ " --no-aa: disable auto-analysis, reducing rtla timerlat cpu usage",
" -b/--bucket-size N: set the histogram bucket size (default 1)",
" -E/--entries N: set the number of entries of the histogram (default 256)",
" --no-irq: ignore IRQ latencies",
@@ -537,13 +542,15 @@ static struct timerlat_hist_params
{"trigger", required_argument, 0, '6'},
{"filter", required_argument, 0, '7'},
{"dma-latency", required_argument, 0, '8'},
+ {"no-aa", no_argument, 0, '9'},
+ {"dump-task", no_argument, 0, '\1'},
{0, 0, 0, 0}
};

/* getopt_long stores the option index here. */
int option_index = 0;

- c = getopt_long(argc, argv, "a:c:C::b:d:e:E:DhH:i:np:P:s:t::T:0123456:7:8:",
+ c = getopt_long(argc, argv, "a:c:C::b:d:e:E:DhH:i:np:P:s:t::T:0123456:7:8:9\1",
long_options, &option_index);

/* detect the end of the options. */
@@ -556,6 +563,7 @@ static struct timerlat_hist_params

/* set thread stop to auto_thresh */
params->stop_total_us = auto_thresh;
+ params->stop_us = auto_thresh;

/* get stack trace */
params->print_stack = auto_thresh;
@@ -699,6 +707,12 @@ static struct timerlat_hist_params
exit(EXIT_FAILURE);
}
break;
+ case '9':
+ params->no_aa = 1;
+ break;
+ case '\1':
+ params->dump_tasks = 1;
+ break;
default:
timerlat_hist_usage("Invalid option");
}
@@ -715,6 +729,12 @@ static struct timerlat_hist_params
if (params->no_index && !params->with_zeros)
timerlat_hist_usage("no-index set with with-zeros is not set - it does not make sense");

+ /*
+ * Auto analysis only happens if stop tracing, thus:
+ */
+ if (!params->stop_us && !params->stop_total_us)
+ params->no_aa = 1;
+
return params;
}

@@ -848,6 +868,7 @@ int timerlat_hist_main(int argc, char *argv[])
struct timerlat_hist_params *params;
struct osnoise_tool *record = NULL;
struct osnoise_tool *tool = NULL;
+ struct osnoise_tool *aa = NULL;
struct trace_instance *trace;
int dma_latency_fd = -1;
int return_value = 1;
@@ -919,6 +940,26 @@ int timerlat_hist_main(int argc, char *argv[])
trace_instance_start(&record->trace);
}

+ if (!params->no_aa) {
+ aa = osnoise_init_tool("timerlat_aa");
+ if (!aa)
+ goto out_hist;
+
+ retval = timerlat_aa_init(aa, params->dump_tasks);
+ if (retval) {
+ err_msg("Failed to enable the auto analysis instance\n");
+ goto out_hist;
+ }
+
+ retval = enable_timerlat(&aa->trace);
+ if (retval) {
+ err_msg("Failed to enable timerlat tracer\n");
+ goto out_hist;
+ }
+
+ trace_instance_start(&aa->trace);
+ }
+
tool->start_time = time(NULL);
timerlat_hist_set_signals(params);

@@ -946,6 +987,10 @@ int timerlat_hist_main(int argc, char *argv[])

if (trace_is_off(&tool->trace, &record->trace)) {
printf("rtla timerlat hit stop tracing\n");
+
+ if (!params->no_aa)
+ timerlat_auto_analysis(params->stop_us, params->stop_total_us);
+
if (params->trace_output) {
printf(" Saving trace to %s\n", params->trace_output);
save_trace_to_file(record->trace.inst, params->trace_output);
@@ -953,12 +998,14 @@ int timerlat_hist_main(int argc, char *argv[])
}

out_hist:
+ timerlat_aa_destroy();
if (dma_latency_fd >= 0)
close(dma_latency_fd);
trace_events_destroy(&record->trace, params->events);
params->events = NULL;
out_free:
timerlat_free_histogram(tool->data);
+ osnoise_destroy_tool(aa);
osnoise_destroy_tool(record);
osnoise_destroy_tool(tool);
free(params);
--
2.39.2