Re: Solaris Priority Paging and Database products.

In article <7rcfod$d00$1_at_nnrp1.deja.com>,   andrew.reardon_at_australia.boeing.com wrote:
> Hi All!
>
> My standpoint on prioroty paging is, why not implement it, because,
*it
> can only help*.
> It's a tweak to the way Solaris manages it's buffercache, and it's a
> tweak for the better.
>
> The white paper
> at http://www.sun.com/sun-on-net/performance/priority_paging.html
claims
> "performance gains between 10-300% on customer workloads". Well I
> certainly haven't seen that kind of dramatic improvement since
> implementing it a few months ago, but I guess it all depends on your
> workload, type of apps used, etc.

I don't agree with "just implement it, because it can only help" as a philosophy. Yes, p.p. is a performance tweak that's designed to improve performance, but it's not necessarily the appropriate performance tweak for all performance problems. In some cases, it might actually be detrimental.

I analogize it to tweaking an engine. The engine that is tweaked to push a car through a superspeedway at 250mph is not necessarily a good engine to pull a tree stump out of the ground. Sure the engine has got great performance, but it's all the wrong kind of performance for the second type of job.

I can see that if this tweak were applied, and executable pages stayed in memory a little longer than data pages, then if those executable pages are no longer needed then those data pages will just have had some of their space stolen by useless executable pages.

       Yousuf Khan

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Share what you know. Learn what you don't. Received on Sun Sep 12 1999 - 03:08:13 CDT