[Gluster-devel] Interesting profile data on tests

[Vijay Bellur]

On 12/30/2015 10:36 AM, Raghavendra Talur wrote:
> This is not comprehensive data but some interesting bits
>
> Average time taken for various commands in our .t files.
>
> * glusterd - 2 second
> * gluster vol start/stop - 3 second
> * gluster vol set/info(any basic gluster cli command) -1 second
> * gluster mount - 2 second
> * gluster add brick - 2 second
> * gluster remove brick - 5 second
> * gluster rebalance start 5 second
> * gluster tier attach/detach - 6 second
>
> The only other single command which takes 1+ second is sleep. Most of
> the other
> external commands we use in bash scripts are not that time taking.
>
>
> Hence,
>
> 1. Don't stop/delete a gluster volume in .t file unless it is part of
> your test. Let the cleanup function handle that.
> 2. Don't call gluster vol info at the start of the test if not required
> 3. Merge as many tests as possible to reduce glusterd starts/vol starts
> and mounts.
> 4. Use sleep only if it is absolutely required.
>
> You can use this bug https://bugzilla.redhat.com/show_bug.cgi?id=1294826
> to send patches to improve test times.
>

Thank you! These are good set of steps that can help in reducing the 
overall time consumed for a regression test run. I also think the larger 
latencies observed in volume operations could be related to the the set 
of fsync()s involved in making configuration state durable in glusterd's 
store. It would be interesting to see if we can use a ramdisk for 
/var/lib/glusterd and check if the latencies would improve.

Regards,
Vijay