Re: Mainline kernel OLTP performance update

On Friday 16 January 2009 17:55:47 Matthew Wilcox wrote:

On Fri, Jan 16, 2009 at 05:46:23PM +1100, Nick Piggin wrote:

quoted

Intel's OLTP shows SLQB is "neutral" to SLAB. That is, literally within
their measurement confidence interval. If it comes down to it, I think we
could get them to do more runs to narrow that down, but we're talking a
couple of tenths of a percent already.

I think I can speak with some measure of confidence for at least the
OLTP-testing part of my company when I say that I have no objection to
Nick's planned merge scheme.

I believe the kernel benchmark group have also done some testing with
SLQB and have generally positive things to say about it (Yanmin added to
the gargantuan cc).

Did slabtop get fixed to work with SLQB?

Yes the old slabtop that works on /proc/slabinfo works with SLQB (ie. SLQB
implements /proc/slabinfo).

Lin Ming recently also ported the SLUB /sys/kernel/slab/ specific slabinfo
tool to SLQB. Basically it reports in-depth internal event counts etc. and
can operate on individual caches, making it very useful for performance
"observability" and tuning.

It is hard to come up with a single set of statistics that apply usefully
to all the allocators. FWIW, it would be a useful tool to port over to
SLAB too, if we end up deciding to go with SLAB.