Re: [PATCH] backend: compare word-at-a-time in bcTruelen

Jeremy Kerr wrote:
>> Speaking of which, what about some performance numbers?
> 
> OK, benchmarks done:
> 
>  http://ozlabs.org/~jk/projects/db/data/postgres.bcTruelen/
> 
> Summary: small increase in performance (~1-2% on my machine), at about 
> 1.5 standard deviations from the mean. Profiles show a decent drop in 
> hits within bcTruelen.
> 
> However: Sysbench seems to be quite heavy with the fixed-width char 
> types, so may end up calling bcTruelen more than most workloads. Would 
> be nice to get some x86 numbers too, but I don't have a suitable machine 
> here.
> 
> So: The increase in performance is positive on this workload, albeit 
> fairly minor. Downside is increased code complexity.

Based on this benchmark, I don't think this patch is worth it..

--   Heikki Linnakangas  EnterpriseDB   http://www.enterprisedb.com