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Re: ITS#3950



--On Friday, January 13, 2006 11:28 PM -0800 Quanah Gibson-Mount <quanah@symas.com> wrote:

I started benchmarking on OpenLDAP 2.3.17 tonight.  I found that on
Solaris, there was no change in performance over previous OpenLDAP
releases.  However, I found that on linux, performance on just the prime
job (which doesn't measure the full performance of the server, just loads
the cache) had dropped from approximately 1500 searches/second to 100
searches/second (15X reduction in speed).

Changing portable.h to #undef REPLACE_BROKEN_YIELD brought performance
back up.

I then tested

# define REPLACE_BROKEN_YIELD 1
# undef HAVE_NANOSLEEP


This also brought performance back up.

So some part of this change likely needs to be reverted, and is also
likely the cause of the performance issue reports seen on -software.



Here is a further update.

First, I note that the above tests, and the following, were all done on a Linux 2.4 kernel. I believe the REPLACE_BROKEN_YIELD bit *must* be disabled for 2.4 kernels.

The results from a full throttle test of 2.3.17 on the linux 2.4 kernel:

REPLACE_BROKEN_YIELD, NANOSLEEP = 535 searches/second average
REPLACE_BROKEN_YIELD, SELECT = 4706 searches/second average
UNDEF REPLACE_BROKEN_YIELD = 8138 searches/second average (and I believe I maxed out my 100MB/s ethernet here, possible it could be higher otherwise)

--Quanah

--
Quanah Gibson-Mount
Product Engineer
Symas Corporation
Packaged, certified, and supported LDAP solutions powered by OpenLDAP:
<http://www.symas.com>