Bug 450415

Summary:	Investigate adding the Pulse-Per-Second (PPS) patch or equivalent
Product:	Red Hat Enterprise MRG	Reporter:	Clark Williams <williams>
Component:	realtime-kernel	Assignee:	Red Hat Real Time Maintenance <rt-maint>
Status:	CLOSED NOTABUG	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	1.0	CC:	bhu, jcm, tglx
Target Milestone:	---	Keywords:	FutureFeature
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Enhancement
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2009-09-23 16:22:06 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description Clark Williams 2008-06-08 01:17:28 UTC

Description of problem:

Many of our customers have expressed a desire to synchronise multiple systems in
a datacenter to sub-millisecond time resolutions. Currently, NTP is unable to
maintain this level of synchronization. We should investigate the utility of
combining a GPS precision time source with either a multi-drop serial interface
or  a dedicated ethernet interface, as a periodic update to NTP.

Comment 1 Clark Williams 2008-06-08 01:19:52 UTC

Ah re-reading my above, I realized that I didn't state that I'm aware that the
current PPS patch is unsuitable for inclusion. We should look at starting from
that and possibly morphing it into a general purpose solution that:

1. Doesn't add it's own system calls
2. Possibly provides a clocksource
3. Doesn't suck

Comment 2 Clark Williams 2008-11-05 21:05:59 UTC

Some links for consideration

LinuxPPS website:
      http://wiki.enneenne.com/index.php/LinuxPPS_support

Seventh repost of PPS patch series to LKML:
      http://linux.derkeiler.com/Mailing-Lists/Kernel/2008-09/msg04640.html

Comment 3 Matt Castelein 2009-02-18 23:02:44 UTC

Would this just be for RHEL, or would Fedora benefit as well?  I would like to have this functionality without breaking kernel updates.

Comment 4 Clark Williams 2009-02-19 00:07:25 UTC

At present we're just talking about it for the MRT RT (realtime) kernel. I don't know of any plans to add it to RHEL or Fedora, since it's not upstream yet.

Comment 5 Beth Uptagrafft 2009-09-22 21:29:31 UTC

Clark, is this still something we want to pursue?

Comment 6 Clark Williams 2009-09-23 16:22:06 UTC

PPS has been added to the 2.6.31 upstream kernel. closing