On Sat, Nov 07, 2020 at 04:41:07AM +0000, zied guermazi wrote:
hi Mathieuis this status still up to date? is there any changes in betweenFYI: on gdb it is possible to trace multi-threaded programs on Intel processors using intel PT. I am not quite sure how this is realized, but I tested it and it works.
Suzuki has done some work on this. Based on his findings doing something such as:
$ perf record -e cs_etm/.../ some_multithread_application
should work. Notice the absence of the --per-thread, -A or -C options. Kernel shark traces on a multi-threaded application yielded positive results. Inspection of the collected traces also showed trace data from different threads.
Have a go at it and let us know how you fare.
Thanks, Mathieu
I am attaching the gdb test source file for it. it can be compiled using " gcc -g ./non-stop.c -o ./non-stop -lpthread" start gdb using "gdb ./non-stop"on gdb execute following commandsb mainrunbreak 27 break 30 thread apply all continue & record btrace thread apply all continue &thread apply all info recinfo threadsset record instruction-history-size 256 thread apply 1 record goto 2 thread apply 2 record goto 4thread apply 1 record instruction-history 1thread apply 2 record instruction-history 1
you can see that gdb collects traces for both threads Kind RegardsZied Guermazi
On Monday, March 2, 2020, 4:23:10 PM GMT+1, Mathieu Poirier <mathieu.poirier@linaro.org> wrote:Hi Andrea,
On Mon, 2 Mar 2020 at 01:46, Andrea Brunato Andrea.Brunato@arm.com wrote:
Good morning,
Is tracing a multi-threaded program a supported use case for perf cs-etm?
It is not a supported case for both PT and Coresight.
Mathieu
If yes, are there any flags that should be specified with perf?
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/* This testcase is part of GDB, the GNU debugger.
Copyright 2015-2019 Free Software Foundation, Inc.
This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with this program. If not, see http://www.gnu.org/licenses/. */
#include <pthread.h>
static int global;
static void * test (void *arg) { unsigned int i;
i = 0; /* bp.1 */ for (; i < 10; ++i) global += i; /* loop */
return arg; /* bp.2 */ }
int main (void) { pthread_t th;
pthread_create (&th, NULL, test, NULL);
test (NULL);
pthread_join (th, NULL);
return 0; /* bp.3 */ }