Re: Proper values for threads and tool-threads

[Mark <mah042@gmail.com>]

Does IIRC mean If I Remember Correctly?

Each machine has 4 physical CPUs. Each CPU has 6 cores. (http://ark.intel.com/Product.aspx?id=46491) So that's 24 real cores, correct?. So if I'm understanding you're suggestion:

tool-threads = 24
threads <= 96

If I set threads above 32 I get the warning mentioned earlier (I assume YMMV means: Your Mileage May Vary). Should I be concerned?

Thank you for replying on a weekend.

On Sun, Jun 5, 2011 at 8:26 PM, Quanah Gibson-Mount <quanah@zimbra.com> wrote:

--On Sunday, June 05, 2011 5:41 PM -0500 Mark <mah042@gmail.com> wrote:

I'm setting up a new installation of OpenLDAP 2.4.25 on RHEL machines
each with 128GB RAM and 4 Intel Xeon E7530 CPUs (6 cores each, each core
supporting two threads). /proc/cpuinfo shows there are 48 processors. The
backend hdb database will eventually have millions of records with
thousands of concurrent readers and writers. Is there a good equation to
use for determining a value for threads and tool-threads? I'd like to
take advantage of the hardware available. I get a warning if I set
threads higher than 32:

olcThreads: value #0: warning, threads=48 larger than twice the default
(2*16=32); YMMV.

I shouldn't be slapcat'ing and slapadd'ing it very often, but like to set
tool-threads to an appropriate value for the hardware.

How many real cores do you have?

Generally tool-threads should be set to that number.

Generally threads should be set to no more than 4 threads per real core IIRC (8 is generally good for 1 or 2 cores, 16 for 4 cores, etc).

--Quanah


--

Quanah Gibson-Mount
Sr. Member of Technical Staff
Zimbra, Inc
A Division of VMware, Inc.
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