DTrace to measure ZFS operations & latency
Linda Kateley
lkateley at kateley.com
Thu Aug 20 21:21:10 UTC 2015
Usually what I will do with those is to try to find a similar probe in
freebsd.
Something like...
#dtrace -l | grep async
or something like that.. to try and find a similar function to trace.
This one looks promising
spa_async_dispatch_vd
Not sure I will be able to quantize on the args though, without more
time...
Hopefully that will give you a start.
On 8/20/15 12:45 PM, Michael W. Lucas wrote:
> Hi,
>
> I'm working on measuring the number & latency of async operations in
> ZFS. (Yes, this is still for the ZFS book.) There's a nice script at
> http://dtrace.org/blogs/ahl/2014/08/31/openzfs-tuning/, but it's
> illumos-specific. I try to run the script on last week's -current and
> get:
>
> # dtrace -s q.d zroot
> dtrace: failed to compile script q.d: line 4: probe description fbt::vdev_queue_max_async_writes:entry does not match any probes
>
> Any chance someone could help me out here?
>
> Thanks,
> ==ml
>
> PS: The script is:
>
> #pragma D option aggpack
> #pragma D option quiet
>
> fbt::vdev_queue_max_async_writes:entry
> {
> self->spa = args[0];
> }
> fbt::vdev_queue_max_async_writes:return
> /self->spa && self->spa->spa_name == $$1/
> {
> @ = lquantize(args[1], 0, 30, 1);
> }
>
> tick-1s
> {
> printa(@);
> clear(@);
> }
>
>
--
Linda Kateley
Kateley Company
Skype ID-kateleyco
http://kateleyco.com
More information about the freebsd-fs
mailing list