Re: Reduce Solaris context switches possible?

alainrtv_at_yahoo.com (Alan) wrote in message news:<fbee32ac.0208162018.282754d_at_posting.google.com>...
> Hi,
>
> I'm looking for an enhancement I may make to my Solaris 2.8 OS.
>
> According to some guy I met at a user group,
> I may lengthen the slice of time given to each process currently
> resident in the run queue.
>
> Maybe it is some bizarre urban legend type thing (or maybe an
> enhancement to something like Solaris 2.3).
>
> Have any of you heard of this Solaris enhancement?
>
> The idea behind this enhancement is that it improves the performance
> of some database related processes like the Oracle kernel.
>
> I assume the performance boost comes as a result of fewer context
> switches per second.

Hi, Alan,

I noticed you cross-posted this to two newsgroups. Oracle does not recommend you change oracle process priority. However, Steve Adams (http://www.ixora.com.au/tips/mystery.doc) did some experiment and claimed that "Despite warnings to the contrary, it does help to raise the operating system priority of both the LGWR and DBWR processes". I hope this adds another voice to this discussion. Note that he says raise the process priority (priocntl as well as renice comes to my mind), not modify dispatch table.

It's unlikely performance improvement results from less context switches. It may well come from longer on-cpu time and less yield(2) calls. You may want to truss LGWR and DBWR for a few minutes and see whether you can gain by altering their priority. As others said, if disk I/O is your bottleneck, this won't help.

Yong Huang Received on Mon Aug 19 2002 - 17:42:23 CDT