* trace spinlock
@ 2010-08-26 6:50 Zhiwei Ying
2010-08-26 6:57 ` Roland McGrath
0 siblings, 1 reply; 2+ messages in thread
From: Zhiwei Ying @ 2010-08-26 6:50 UTC (permalink / raw)
To: systemtap
Hi,
I am trying to trace the spinlock/spinunlock, but there is something
weired in the output. In some cases, the parm of spinlock becomes "?"
Does anyone know what's reason? And how to fix this?
Thanks,
Zhiwei
tracelock.stp
probe kernel.function("spin_lock").inline
{
name = execname()
printf("exec(%s) %s %s\n", name, probefunc(), $$parms)
}
probe kernel.function("spin_unlock").inline
{
name = execname()
printf("exec(%s) %s %s\n", name, probefunc(), $$parms)
}
output:
exec(rfs_update_rino) spin_lock lock=0xc0958a00
exec(rfs_update_rino) spin_unlock lock=0xc0958a00
exec(rfs_update_rino) spin_lock lock=?
exec(rfs_update_rino) spin_unlock lock=?
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: trace spinlock
2010-08-26 6:50 trace spinlock Zhiwei Ying
@ 2010-08-26 6:57 ` Roland McGrath
0 siblings, 0 replies; 2+ messages in thread
From: Roland McGrath @ 2010-08-26 6:57 UTC (permalink / raw)
To: Zhiwei Ying; +Cc: systemtap
> I am trying to trace the spinlock/spinunlock, but there is something
> weired in the output. In some cases, the parm of spinlock becomes "?"
> Does anyone know what's reason? And how to fix this?
That means the variables were not available in those probe sites.
Try -vvv and look for "variable location problem" messages.
Thanks,
Roland
^ permalink raw reply [flat|nested] 2+ messages in thread
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