Bug 1437330

Summary:	Sharding: Fix a performance bug
Product:	[Community] GlusterFS	Reporter:	Krutika Dhananjay <kdhananj>
Component:	sharding	Assignee:	Krutika Dhananjay <kdhananj>
Status:	CLOSED CURRENTRELEASE	QA Contact:	bugs <bugs>
Severity:	unspecified	Docs Contact:
Priority:	unspecified
Version:	3.8	CC:	bugs, kdhananj, sasundar
Target Milestone:	---	Keywords:	Triaged
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:	glusterfs-3.8.11	Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:	1436739	Environment:
Last Closed:	2017-04-11 09:07:22 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	1436739, 1438706
Bug Blocks:	1411323, 1431410

Description Krutika Dhananjay 2017-03-30 06:01:31 UTC

+++ This bug was initially created as a clone of Bug #1436739 +++

Description of problem:

As per Sanjay Rao's inputs, there was a performance drop in random reads fio workload when run through vms hosted on sharded volumes.

Volume profile indicated a big difference between the number of lookups sent by FUSE and number of lookups received by individual bricks.

Through code reading, it was found that there is a performance bug in shard which was causing the translator to trigger unusually high number of lookups for cache invalidation even when there was no modification to the file.


Version-Release number of selected component (if applicable):


How reproducible:


Steps to Reproduce:
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Actual results:


Expected results:


Additional info:

--- Additional comment from Worker Ant on 2017-03-28 10:23:33 EDT ---

REVIEW: https://review.gluster.org/16961 (features/shard: Pass the correct iatt for cache invalidation) posted (#1) for review on master by Krutika Dhananjay (kdhananj)

--- Additional comment from Worker Ant on 2017-03-30 01:48:38 EDT ---

REVIEW: https://review.gluster.org/16961 (features/shard: Pass the correct iatt for cache invalidation) posted (#2) for review on master by Krutika Dhananjay (kdhananj)

Comment 1 Worker Ant 2017-03-30 06:02:30 UTC

REVIEW: https://review.gluster.org/16968 (features/shard: Pass the correct iatt for cache invalidation) posted (#1) for review on release-3.8 by Krutika Dhananjay (kdhananj)

Comment 3 Worker Ant 2017-04-04 08:54:27 UTC

COMMIT: https://review.gluster.org/16968 committed in release-3.8 by jiffin tony Thottan (jthottan) 
------
commit 7920d7f3879ca5971d4e7ba569534934bfa676e8
Author: Krutika Dhananjay <kdhananj>
Date:   Tue Mar 28 19:26:41 2017 +0530

    features/shard: Pass the correct iatt for cache invalidation
    
            Backport of: https://review.gluster.org/16961
    
    This fixes a performance issue with shard which was causing
    the translator to trigger unusually high number of lookups
    for cache invalidation even when there was no modification to
    the file.
    
    In shard_common_stat_cbk(), it is local->prebuf that contains the
    aggregated size and block count as opposed to buf which only holds the
    attributes for the physical copy of base shard. Passing buf for
    inode_ctx invalidation would always set refresh to true since the file
    size in inode ctx contains the aggregated size and would never be same
    as @buf->ia_size. This was leading to every write/read being preceded
    by a lookup on the base shard even when the file underwent no
    modification.
    
    Change-Id: I85940b4b33e77b98e97e277d880ab35b1496c89a
    BUG: 1437330
    Signed-off-by: Krutika Dhananjay <kdhananj>
    Reviewed-on: https://review.gluster.org/16968
    Smoke: Gluster Build System <jenkins.org>
    Reviewed-by: Pranith Kumar Karampuri <pkarampu>
    NetBSD-regression: NetBSD Build System <jenkins.org>
    CentOS-regression: Gluster Build System <jenkins.org>
    Reviewed-by: jiffin tony Thottan <jthottan>

Comment 4 Niels de Vos 2017-04-11 09:07:22 UTC

This bug is getting closed because a release has been made available that should address the reported issue. In case the problem is still not fixed with glusterfs-3.8.11, please open a new bug report.

glusterfs-3.8.11 has been announced on the Gluster mailinglists [1], packages for several distributions should become available in the near future. Keep an eye on the Gluster Users mailinglist [2] and the update infrastructure for your distribution.

[1] http://lists.gluster.org/pipermail/packaging/2017-April/000289.html
[2] https://www.gluster.org/pipermail/gluster-users/