Russ,
I use some variation of the following attached script. It is derived from
plockstat sample code.
rick
On Thu, Nov 15, 2007 at 11:28:18AM -0800, Russ Weeks wrote:
>
> Hi,
>
> I'm looking for a way to measure mutex contention in a Java app running
> on Solaris 10. I started off by using the dvmti probes
> monitor-contended-enter and monitor-contended-entered, but I found that
> the act of observing these probes skewed my program performance to the
> point that the measurements weren't useful.
>
> I'm thinking of taking a lower-level approach to this. Is it correct to
> assume that Java object monitors are going to map to a lwp_mutex at some
> point in the call stack? I replaced my dvmti-based script with this:
>
> syscall::lwp_mutex*:entry
> {
> self->ts[probefunc] = timestamp;
> }
>
> syscall::lwp_mutex*:return
> /self->ts[probefunc] != 0/
> {
> duration = timestamp - self->ts[probefunc];
> @times[ tid ] = quantize( duration );
> self->ts[probefunc] = 0;
> }
>
> And the timings are pretty much what I'd expect, within an order of
> magnitude. Can anybody suggest any improvements here, or am I totally
> off-base?
>
> Thanks,
>
> Russ
> _______________________________________________
> dtrace-discuss mailing list
> [email protected]
--
Rickey C. Weisner
Software Development and Performance Specialist
Sun Microsystems, INC
cell phone: 615-308-1147
email: [EMAIL PROTECTED]
#!/usr/sbin/dtrace -s
#pragma D option bufpolicy=ring
#pragma D option aggsize=256m
#pragma D option strsize=1024
plockstat$1:::rw-acquire
{
self->rwhold[arg0] = timestamp;
}
plockstat$1:::mutex-acquire
/arg1 == 0 /
{
mtxhold[arg0] = timestamp;
}
plockstat$1:::rw-release
/self->rwhold[arg0] && arg1 == 1/
{
@rw_w_hold[arg0, jstack(5)] = avg(timestamp - self->rwhold[arg0]);
self->rwhold[arg0] = 0;
}
plockstat$1:::rw-release
/self->rwhold[arg0]/
{
@rw_r_hold[arg0, jstack(5)] = avg(timestamp - self->rwhold[arg0]);
self->rwhold[arg0] = 0;
}
plockstat$1:::mutex-release
/mtxhold[arg0] && arg1 == 0/
{
@mtx_hold[arg0, jstack(5)] = avg(timestamp - mtxhold[arg0]);
mtxhold[arg0] = 0;
}
plockstat$1:::rw-block
{
self->rwblock[arg0] = timestamp;
}
plockstat$1:::mutex-block
{
self->mtxblock[arg0] = timestamp;
}
plockstat$1:::mutex-spin
{
self->mtxspin[arg0] = timestamp;
}
plockstat$1:::rw-acquire
/self->rwblock[arg0] && arg1 == 1/
{
@rw_w_block[arg0, jstack(5)] =
avg(timestamp - self->rwblock[arg0]);
self->rwblock[arg0] = 0;
}
plockstat$1:::rw-acquire
/self->rwblock[arg0]/
{
@rw_r_block[arg0, jstack(5)] =
avg(timestamp - self->rwblock[arg0]);
self->rwblock[arg0] = 0;
}
plockstat$1:::mutex-block
/self->mtxspin[arg0]/
{
@mtx_vain_spin[arg0, jstack(5)] =
avg(timestamp - self->mtxspin[arg0]);
self->mtxspin[arg0] = 0;
}
plockstat$1:::mutex-acquire
/self->mtxspin[arg0]/
{
@mtx_spin[arg0, jstack(5)] =
avg(timestamp - self->mtxspin[arg0]);
self->mtxspin[arg0] = 0;
}
plockstat$1:::mutex-acquire
/self->mtxblock[arg0]/
{
@mtx_block[arg0, jstack(5)] =
avg(timestamp - self->mtxblock[arg0]);
self->mtxblock[arg0] = 0;
}
plockstat$1:::mutex-error
/self->mtxblock[arg0]/
{
self->mtxblock[arg0] = 0;
}
plockstat$1:::rw-error
/self->rwblock[arg0]/
{
self->rwblock[arg0] = 0;
}
plockstat$1:::mutex-error
/self->mtxspin[arg0]/
{
self->mtxspin[arg0] = 0;
}
tick-10sec
{
trunc(@mtx_hold,10);
trunc(@mtx_vain_spin,10);
trunc(@mtx_spin,10);
trunc(@mtx_block,10);
printf(" mutex hold events =================================== \n");
printa(@mtx_hold);
printf(" mutex vain spin events ===================================
\n");
printa(@mtx_vain_spin);
printf(" mutex spin events =================================== \n");
printa(@mtx_spin);
printf(" mutex block events =================================== \n");
printa(@mtx_block);
clear(@mtx_hold);
clear(@mtx_vain_spin);
clear(@mtx_spin);
clear(@mtx_block);
exit(0);
}
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