From cdca4f4e5e8ea1c21417d86a0b2ed6af282cbb6e Mon Sep 17 00:00:00 2001 From: Daniel Bristot de Oliveira Date: Tue, 6 Jun 2023 18:12:23 +0200 Subject: rtla/timerlat_top: Add timerlat user-space support Add the support for running timerlat threads in user-space. In this mode, enabled with -u/--user-threads, timerlat dispatches user-space processes that will loop in the timerlat_fd, measuring the overhead for going to user-space and then returning to the kernel - in addition to the existing measurements. Here is one example of the tool's output with -u enabled: $ sudo timerlat top -u -d 600 -q Timer Latency 0 00:10:01 | IRQ Timer Latency (us) | Thread Timer Latency (us) | Ret user Timer Latency (us) CPU COUNT | cur min avg max | cur min avg max | cur min avg max 0 #600001 | 0 0 0 3 | 2 1 2 9 | 3 2 3 15 1 #600001 | 0 0 0 2 | 2 1 2 13 | 2 2 3 18 2 #600001 | 0 0 0 10 | 2 1 2 16 | 3 2 3 20 3 #600001 | 0 0 0 7 | 2 1 2 10 | 3 2 3 11 4 #600000 | 0 0 0 16 | 2 1 2 41 | 3 2 3 58 5 #600000 | 0 0 0 3 | 2 1 2 10 | 3 2 3 13 6 #600000 | 0 0 0 5 | 2 1 2 7 | 3 2 3 10 7 #600000 | 0 0 0 1 | 2 1 2 7 | 3 2 3 10 The tuning setup like -p or -C work for the user-space threads as well. Link: https://lkml.kernel.org/r/758ad2292a0a1d884138d08219e1a0f572d257a2.1686066600.git.bristot@kernel.org Cc: William White Cc: Jonathan Corbet Tested-by: Juri Lelli Signed-off-by: Daniel Bristot de Oliveira Signed-off-by: Steven Rostedt (Google) --- tools/tracing/rtla/src/timerlat_u.h | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) create mode 100644 tools/tracing/rtla/src/timerlat_u.h (limited to 'tools/tracing/rtla/src/timerlat_u.h') diff --git a/tools/tracing/rtla/src/timerlat_u.h b/tools/tracing/rtla/src/timerlat_u.h new file mode 100644 index 000000000000..661511908957 --- /dev/null +++ b/tools/tracing/rtla/src/timerlat_u.h @@ -0,0 +1,18 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2023 Red Hat Inc, Daniel Bristot de Oliveira + */ + +struct timerlat_u_params { + /* timerlat -> timerlat_u: user-space threads can keep running */ + int should_run; + /* timerlat_u -> timerlat: all timerlat_u threads left, no reason to continue */ + int stopped_running; + + /* threads config */ + cpu_set_t *set; + char *cgroup_name; + struct sched_attr *sched_param; +}; + +void *timerlat_u_dispatcher(void *data); -- cgit v1.2.3