[openstack-dev] [nova] [all] Excessively high greenlet default + excessively low connection pool defaults leads to connection pool latency, timeout errors, idle database connections / workers

Roman Podoliaka rpodolyaka at mirantis.com
Tue Feb 23 18:24:54 UTC 2016

That's what I tried first :)

For some reason load distribution was still uneven. I'll check this
again, maybe I missed something.

On Tue, Feb 23, 2016 at 5:37 PM, Chris Friesen
<chris.friesen at windriver.com> wrote:
> On 02/23/2016 05:25 AM, Roman Podoliaka wrote:
>> So looks like it's two related problems here:
>> 1) the distribution of load between workers is uneven. One way to fix
>> this is to decrease the default number of greenlets in pool [2], which
>> will effectively cause a particular worker to give up new connections
>> to other forks, as soon as there are no more greenlets available in
>> the pool to process incoming requests. But this alone will *only* be
>> effective when the concurrency level is greater than the number of
>> greenlets in pool. Another way would be to add a context switch to
>> eventlet accept() loop [8] right after spawn_n() - this is what I've
>> got with greenthread.sleep(0.05) [9][10] (the trade off is that we now
>> only can accept() 1/ 0.05 = 20 new connections per second per worker -
>> I'll try to experiment with numbers here).
> Would greenthread.sleep(0) be enough to trigger a context switch?
> Chris
> __________________________________________________________________________
> OpenStack Development Mailing List (not for usage questions)
> Unsubscribe: OpenStack-dev-request at lists.openstack.org?subject:unsubscribe
> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev

More information about the OpenStack-dev mailing list