Re: ipc,sem: sysv semaphore scalability

From: Linus Torvalds
Date: Wed Mar 20 2013 - 16:56:20 EST

On Wed, Mar 20, 2013 at 1:49 PM, Linus Torvalds
<torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
> It *would* be lovely to see this run with the actual Swingbench
> numbers. The microbenchmark always looked much nicer. Do the
> additional multi-semaphore scalability patches on top of Davidlohr's
> patches help with the swingbench issue, or are we still totally
> swamped by the ipc lock there?
> Maybe there were already numbers for that, but the last swingbench
> numbers I can actually recall was from before the finer-grained
> locking..

Ok, and if the spinlock is still a big deal even with the finer
granularity, it might be interesting to hear if Michel's fast locks
make a difference. I'm guessing that this series might actually make
it easier/cleaner to do the semaphore locking using another lock,
since the ipc_lock got split up and out...

I think Michel did it for some socket code too. I think that was
fairly independent and was for netperf.

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