On Thu, Oct 11, 2018 at 08:18:21AM +0530, Krishna Kumar (Engineering) wrote:
> Hi Willy,
>
> Thank you very much for the in-depth analysis and configuration setting
> suggestions.
> I believe I have got the 3 key items to continue based on your mail:
>
> 1. Thread pinning
> 2. Fix system irq pinning accordingly
> 3. Listen on all threads.
>
> I will post the configuration changes and the results.
By the way, please pull the latest master fixes. I've addressed two issues
there with locking :
- one where the scheduler work was slightly too high, increasing the time
spent on RQ lock
- another one where I messed up on a fix, causing lock-free pools to be
disabled (as seen in your output, where the POOL lock appears a lot)
On some tests I've run here, I've found the stick-tables lock to be a
bottleneck when tracking is enabled. I don't have a short-term solution
to this, but looking at the code it's obvious that it can significantly
be improved (though it will take quite some time). I'll probably at least
try to replace it with an RW lock as I think it could improve the situation.
The FD lock is another one requiring some lift-up. I'm certain it's possible,
I just don't know if it will not degrade low-thread count performance by
using too many atomic ops instead. We'll have to experiment.
Cheers,
Willy
