[Date Prev][Date Next] [Chronological] [Thread] [Top]

Re: [JunkMail] Re: Tuning cachesize

--On Thursday, February 07, 2008 10:43 AM -0800 Howard Chu <hyc@symas.com> wrote:

Quanah Gibson-Mount wrote:
Slapd tuning:

"threads":  This directive sets the number of threads that slapd uses to
process requests.   What this value should be I've generally found to be
a function of the number of "real" cores on the system.  I.e., on a 2
CPU box with one core each, I set this to 8, or 4 threads per real core.
This is a "read" maximized value.  The more threads that are configured
per core, the slower slapd responds for "read" operations.  On the flip
side, it appears to handle write operations faster in a heavy write/low
read scenario.

The upper bound for good read performance appears to be 16 threads (which also happens to be slapd's default). This is also the setting I used when benchmarking the 8-core AMD and Intel servers; increasing beyond that consumed more CPU time but didn't improve throughput. http://connexitor.com/blog/pivot/entry.php?id=191

Okay, so 8 or 16 threads then. Because I know that on my dual-CPU boxes, 16 was definitely less performant than 8 threads.



Quanah Gibson-Mount
Principal Software Engineer
Zimbra, Inc
Zimbra ::  the leader in open source messaging and collaboration