Re: Redhat 7.2.93 performance (was:Re: PostgreSQL 7.2.1-2PGDG RPMs available for RedHat-skipjack 7.2.93 and RedHat 6.2/SPARC)

Lamar Owen wrote:

>>The low-latency and preemptible patches are not meant for performance
>>gains, but for responsiveness, and are not designed to be used in servers,
>>only in workstations/desktops.
>>
>
>ISTM that improving interactive performance would also improve multiuser
>performance in a server, as low latency and kernel preemption can increase
>multiuser server responsiveness.
>
responsiveness != performance IT works OK for a low number of
concurrent users/processes to increase percieved performance, but to get
real gains on large systems with large numebrs of users and processes
you actually decrease the responsiveness of individual tasks (IE make
the system a little less likely to context switch or pre-empt) and
schedual in batches or clusters rather than one-at-a-time. For a
desktop/workstation this would be insane, and drive a user to kill
someone, but for systems that handle several hundred users (interactive
or not) this improves overall perfomance.

2.4.18 has a lot of work done to the VM, but most importantly has work
done to the queue elevator code, thats probably whats doing most of the
work (throttling big writers) of seeing better overall system performance.