Glance

Improved concurrent eventlet thread performance

Bug #1021002 reported by Stuart McLaren on 2012-07-04

This bug affects 1 person

Affects		Status	Importance	Assigned to	Milestone
	Glance	Fix Released	Wishlist	Stuart McLaren	Glance 2012.2 "folsom"

Bug Description

When multiple clients are uploading/downloading images some eventlet threads can get starved. This
happens in particular when multiple requests land on the same Glance worker process.

This has been seen on Glance when using https, and probably will also occur for 'fast' clients, as described
in some depth here:

https://github.com/openstack/swift/commit/783f16035a8e251d2138eb5bbaa459e9e4486d90

Revision history for this message

Stuart McLaren (stuart-mclaren) wrote on 2012-07-04:

Plot showing improvement in concurrency for multiple uploads when 'sleep(0)' is inserted Edit (18.3 KiB, image/png)

Revision history for this message

OpenStack Infra (hudson-openstack) wrote on 2012-07-04: Fix proposed to glance (master)

Fix proposed to branch: master
Review: https://review.openstack.org/9330

Changed in glance:
assignee:	nobody → Stuart McLaren (stuart-mclaren)
status:	New → In Progress

Brian Waldon (bcwaldon) on 2012-07-04

summary:	- Improved concurrency + Improved concurrent eventlet thread performance
Changed in glance:
importance:	Undecided → Wishlist
milestone:	none → folsom-3

Revision history for this message

OpenStack Infra (hudson-openstack) wrote on 2012-07-05: Fix merged to glance (master)

Reviewed: https://review.openstack.org/9330
Committed: http://github.com/openstack/glance/commit/70e9690830653ed92d15c4a696cae8778c635206
Submitter: Jenkins
Branch: master

commit 70e9690830653ed92d15c4a696cae8778c635206
Author: Stuart McLaren <email address hidden>
Date: Wed Jul 4 16:38:07 2012 +0000

Improve eventlet concurrency when uploading/downloading.

    When uploading/downloading multiple images using the
    same glance-api worker process some of its eventlet
    threads can become starved. Inserting statements to
    trigger cooperative yields, ie sleep(0), allows fairer
    scheduling of the other eventlet threads.

Fixes LP Bug #1021002.

Change-Id: I5a8f255e9507d18813d07d418e6acefa10d9f6bb