Wall-clock times

[Andrew M. <an...@ch...>]

Hi,

I'm trying to track down where some code is spending time when it's
_not_ using CPU. It's going to be something like blocking on select()
or waiting for a lock, but I'm not sure exactly where. Therefor I
want the source annotated with wall-time spent in each block, rather
than CPU time.

Can I use oprofile to help? I've a Pentium 4 Xeon (with HT turned
off). As far as I can tell, what I want to do is sample on something
like GLOBAL_POWER_EVENTS, but for all ticks, not just "active"
ones. oprofile doesn't seem to let me modify the unit mask on this
event.

Second best, I thought that I could just use RTC, but it doesn't seem
to like that either:

# op_start --vmlinux=/boot/vmlinux-2.4.20-bigmem --rtc-value=4096
You haven't specified what events you would like to count, e.g.
op_start ... --ctr0-event=CPU_CLK_UNHALTED --ctr0-count=600000
Enter op_start --help for full options

Any suggestions?

Thanks,

Andrew.

-- 
Andrew Mobbs - http://www.chiark.greenend.org.uk/~andrewm/