lkml.org 
[lkml]   [2014]   [Jun]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Subject[BUG] perf: can not resolve symbols for forked threads
Date
Hi

I got the below output that shows perf can not resolve symbols for forked threads. I did a system-wide collection from all CPUs after the application hello run.

-bash-4.1$ ./perf --version
perf version 3.16.rc1.ge99cfa2
-bash-4.1$ ./hello & ./perf record -a sleep 5
-bash-4.1$ ./perf report
# Overhead Command Shared Object Symbol
# ........ ........... .................. .............................
#
54.77% hello [unknown] [.] 0x0000000000400610
28.59% hello [unknown] [.] 0x0000000000400615
16.53% hello [unknown] [.] 0x000000000040061f
0.01% hello [kernel.kallsyms] [k] __rcu_process_callbacks
0.01% perf [kernel.kallsyms] [k] copy_user_generic_string
0.01% sleep [kernel.kallsyms] [k] filemap_fault
....

/***************************************************************************** FILE: hello.c
** DESCRIPTION:
** A "hello world" Pthreads program to trigger this bug.
***************************************************************************/
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#define NUM_THREADS 5

void foo(void)
{
long i = 1000000000;
while (i--) {
;
}
}

void *PrintHello(void *threadid)
{
long tid;
tid = (long)threadid;
printf("Hello World! It's me, thread #%ld!\n", tid);
foo();
pthread_exit(NULL);
}

int main(int argc, char *argv[])
{
pthread_t threads[NUM_THREADS];
int rc;
long t;
for(t=0;t<NUM_THREADS;t++){
printf("In main: creating thread %ld\n", t);
rc = pthread_create(&threads[t], NULL, PrintHello, (void *)t);
if (rc){
printf("ERROR; return code from pthread_create() is %d\n", rc);
exit(-1);
}
}

/* Last thing that main() should do */
pthread_exit(NULL);
}

Thanks
-Tony


\
 
 \ /
  Last update: 2014-06-19 10:21    [W:0.057 / U:0.072 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site