Re: PostgreSQL performance on FreeBSD

On 12 August 2014 11:09, John Baldwin <jhb_at_freebsd.org> wrote:
> On Wednesday, July 16, 2014 1:52:45 pm Adrian Chadd wrote:
>> Hi!
>>
>>
>> On 16 July 2014 06:29, Konstantin Belousov <kostikbel_at_gmail.com> wrote:
>> > On Fri, Jun 27, 2014 at 03:56:13PM +0300, Konstantin Belousov wrote:
>> >> Hi,
>> >> I did some measurements and hacks to see about the performance and
>> >> scalability of PostgreSQL 9.3 on FreeBSD, sponsored by The FreeBSD
>> >> Foundation.
>> >>
>> >> The results are described in https://kib.kiev.ua/kib/pgsql_perf.pdf.
>> >> The uncommitted patches, referenced in the article, are available as
>> >> https://kib.kiev.ua/kib/pig1.patch.txt
>> >> https://kib.kiev.ua/kib/patch-2
>> >
>> > A followup to the original paper.
>> >
>> > Most importantly, I identified the cause for the drop on the graph
>> > after the 30 clients, which appeared to be the debugging version
>> > of malloc(3) in libc.
>> >
>> > Also there are some updates on the patches.
>> >
>> > New version of the paper is available at
>> > https://www.kib.kiev.ua/kib/pgsql_perf_v2.0.pdf
>> > The changes are marked as 'update for version 2.0'.
>>
>> Would you mind trying a default (non-PRODUCTION) build, but with junk
>> filling turned off?
>>
>> adrian_at_adrian-hackbox:~ % ls -l /etc/malloc.conf
>>
>> lrwxr-xr-x  1 root  wheel  10 Jun 24 04:37 /etc/malloc.conf -> junk:false
>>
>> That fixes almost all of the malloc debug performance issues that I
>> see without having to recompile.
>>
>> I'd like to know if you see any after that.
>
> OTOH, I have actually seen junk profiling _improve_ performance in certain
> cases as it forces promotion of allocated pages to superpages since all pages
> are dirtied.  (I have a local hack that adds a new malloc option to explicitly
> memset() new pages allocated via mmap() that gives the same benefit without
> the junking overheadon each malloc() / free(), but it does increase physical
> RAM usage.)

Hm. this isn't a jemalloc config option?


-a