From: liang xie <xieliang007@gmail.com>
To: systemtap@sourceware.org
Subject: How to get the detailed kernel stack trace if specified fuction takes too long to finish?
Date: Fri, 28 Mar 2014 04:22:00 -0000 [thread overview]
Message-ID: <CADu=CFo=AtrBJLacPTa_6EfQA7vao=bSuT2Yns45x-hWYfmWZA@mail.gmail.com> (raw)
Hi all,
Probably it's a newbie question, to be honest, i am new to SystemTap,
currently i want to capture the kernel stack trace if "sys_write" runs
too long, if that i could know where it sucks.
My OS:2.6.32-220.el6.x86_64
# stap -V
Systemtap translator/driver (version 1.6/0.152 non-git sources)
My tried script:
global i=0
global tb=0
global te=0
probe kernel.function("sys_write") {
tb=gettimeofday_us();
}
probe kernel.function("sys_write").return {
te=gettimeofday_us();
if(te-tb > 100000) {
i++;
printf("time_us: %d\n", te-tb);
print_backtrace();
if(i > 15) {
exit();
}
}
}
# stap -x <pid> xxx.stp
time_us: 226795
Returning from: 0xffffffff81176f90 : sys_write+0x0/0x90 [kernel]
Returning to : 0xffffffff8100b0f2 : system_call_fastpath+0x16/0x1b [kernel]
time_us: 101400
Returning from: 0xffffffff81176f90 : sys_write+0x0/0x90 [kernel]
Returning to : 0xffffffff8100b0f2 : system_call_fastpath+0x16/0x1b [kernel]
time_us: 527853
Returning from: 0xffffffff81176f90 : sys_write+0x0/0x90 [kernel]
Returning to : 0xffffffff8100b0f2 : system_call_fastpath+0x16/0x1b [kernel]
time_us: 133948
Returning from: 0xffffffff81176f90 : sys_write+0x0/0x90 [kernel]
Returning to : 0xffffffff8100b0f2 : system_call_fastpath+0x16/0x1b [kernel]
It doesn't show my "expected" kernel stack trace,e.g. file system or
block layer related stack trace. How to archive that? Any pointers
will be highly appreciated!
Best,
Liang
next reply other threads:[~2014-03-28 4:22 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-28 4:22 liang xie [this message]
2014-03-28 16:56 ` Frank Ch. Eigler
2014-03-28 17:06 ` Josh Stone
2014-04-02 10:25 ` liang xie
2014-04-02 16:32 ` Josh Stone
2014-04-03 2:47 ` liang xie
2014-04-03 16:24 ` Josh Stone
2014-04-08 2:15 ` liang xie
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