From a23c05fd76cf4ad27e0c74f7a93e7b089e94a55c Mon Sep 17 00:00:00 2001 From: Daniel Bristot de Oliveira Date: Tue, 6 Feb 2024 15:32:06 +0100 Subject: tools/rtla: Add -U/--user-load option to timerlat The timerlat tracer provides an interface for any application to wait for the timerlat's periodic wakeup. Currently, rtla timerlat uses it to dispatch its user-space workload (-u option). But as the tracer interface is generic, rtla timerlat can also be used to monitor any workload that uses it. For example, a user might place their own workload to wait on the tracer interface, and monitor the results with rtla timerlat. Add the -U option to rtla timerlat top and hist. With this option, rtla timerlat will not dispatch its workload but only setting up the system, waiting for a user to dispatch its workload. The sample code in this patch is an example of python application that loops in the timerlat tracer fd. To use it, dispatch: # rtla timerlat -U In a terminal, then run the python program on another terminal, specifying the CPU to run it. For example, setting on CPU 1: #./timerlat_load.py 1 Then rtla timerlat will start printing the statistics of the ./timerlat_load.py app. An interesting point is that the "Ret user Timer Latency" value is the overall response time of the load. The sample load does a memory copy to exemplify that. The stop tracing options on rtla timerlat works in this setup as well, including auto analysis. Link: https://lkml.kernel.org/r/36e6bcf18fe15c7601048fd4c65aeb193c502cc8.1707229706.git.bristot@kernel.org Cc: Jonathan Corbet Cc: Masami Hiramatsu Signed-off-by: Daniel Bristot de Oliveira --- tools/tracing/rtla/src/timerlat_hist.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) (limited to 'tools/tracing/rtla/src/timerlat_hist.c') diff --git a/tools/tracing/rtla/src/timerlat_hist.c b/tools/tracing/rtla/src/timerlat_hist.c index dbf154082f95..8bd51aab6513 100644 --- a/tools/tracing/rtla/src/timerlat_hist.c +++ b/tools/tracing/rtla/src/timerlat_hist.c @@ -39,6 +39,7 @@ struct timerlat_hist_params { int hk_cpus; int no_aa; int dump_tasks; + int user_workload; int user_hist; cpu_set_t hk_cpu_set; struct sched_attr sched_param; @@ -534,6 +535,7 @@ static void timerlat_hist_usage(char *usage) " d:runtime[us|ms|s]:period[us|ms|s] - use SCHED_DEADLINE with runtime and period", " in nanoseconds", " -u/--user-threads: use rtla user-space threads instead of in-kernel timerlat threads", + " -U/--user-load: enable timerlat for user-defined user-space workload", NULL, }; @@ -595,6 +597,7 @@ static struct timerlat_hist_params {"thread", required_argument, 0, 'T'}, {"trace", optional_argument, 0, 't'}, {"user-threads", no_argument, 0, 'u'}, + {"user-load", no_argument, 0, 'U'}, {"event", required_argument, 0, 'e'}, {"no-irq", no_argument, 0, '0'}, {"no-thread", no_argument, 0, '1'}, @@ -613,7 +616,7 @@ static struct timerlat_hist_params /* 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:u0123456:7:8:9\1", + c = getopt_long(argc, argv, "a:c:C::b:d:e:E:DhH:i:np:P:s:t::T:uU0123456:7:8:9\1", long_options, &option_index); /* detect the end of the options. */ @@ -724,6 +727,9 @@ static struct timerlat_hist_params params->trace_output = "timerlat_trace.txt"; break; case 'u': + params->user_workload = 1; + /* fallback: -u implies in -U */ + case 'U': params->user_hist = 1; break; case '0': /* no irq */ @@ -985,7 +991,7 @@ int timerlat_hist_main(int argc, char *argv[]) } } - if (params->cgroup && !params->user_hist) { + if (params->cgroup && !params->user_workload) { retval = set_comm_cgroup("timerlat/", params->cgroup_name); if (!retval) { err_msg("Failed to move threads to cgroup\n"); @@ -1049,7 +1055,7 @@ int timerlat_hist_main(int argc, char *argv[]) tool->start_time = time(NULL); timerlat_hist_set_signals(params); - if (params->user_hist) { + if (params->user_workload) { /* rtla asked to stop */ params_u.should_run = 1; /* all threads left */ @@ -1086,14 +1092,14 @@ int timerlat_hist_main(int argc, char *argv[]) break; /* is there still any user-threads ? */ - if (params->user_hist) { + if (params->user_workload) { if (params_u.stopped_running) { debug_msg("timerlat user-space threads stopped!\n"); break; } } } - if (params->user_hist && !params_u.stopped_running) { + if (params->user_workload && !params_u.stopped_running) { params_u.should_run = 0; sleep(1); } -- cgit v1.2.3-70-g09d2