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Bug 1549698

Summary:	ceph tcmu-runner perf changes
Product:	[Red Hat Storage] Red Hat Ceph Storage	Reporter:	Mike Christie <mchristi>
Component:	iSCSI	Assignee:	Mike Christie <mchristi>
Status:	CLOSED ERRATA	QA Contact:	Tejas <tchandra>
Severity:	medium	Docs Contact:	Aron Gunn <agunn>
Priority:	low
Version:	3.0	CC:	agunn, ceph-eng-bugs, ceph-qe-bugs, jbiao, jdillama, mchristi, mkasturi, tchandra
Target Milestone:	z3
Target Release:	3.0
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:	tcmu-runner-1.3.0-0.4.2.el7cp	Doc Type:	Bug Fix
Doc Text:	.Tuning the kernel notifications for `tcmu-runner` Previously, `tcmu-runner` would wait to notify the kernel once all outstanding commands had completed. This caused higher latency for commands that were at the beginning of the queue. With this release, `tcmu-runner` will notify the kernel once the first command completes. Batching multiple commands completions together to notify the kernel will still occur, if multiple commands complete around the same time.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2018-05-15 18:20:29 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:
Bug Blocks:	1562459

Description Mike Christie 2018-02-27 16:46:42 UTC

Description of problem:

tcmu-runner tries to batch request completions, but this can result in lower IOPs and higher latency due to the first requests having to wait for the last ones to complete.

A modified version of this patch

[TODO for the patch is here https://github.com/open-iscsi/tcmu-runner/issues/359#issuecomment-360187930]:
https://github.com/open-iscsi/tcmu-runner/issues/359#issuecomment-359687757

will be merged upstream and needs to be brought into ceph's tcmu-runner repo.

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


How reproducible:


Steps to Reproduce:
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Actual results:


Expected results:


Additional info:

Comment 3 Jason Dillaman 2018-03-30 13:53:11 UTC

*** Bug 1562390 has been marked as a duplicate of this bug. ***

Comment 7 Ken Dreyer (Red Hat) 2018-05-03 17:29:40 UTC

*** Bug 1565570 has been marked as a duplicate of this bug. ***

Comment 12 errata-xmlrpc 2018-05-15 18:20:29 UTC

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2018:1563