LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: John <shill@free.fr>
To: linux-kernel@vger.kernel.org
Cc: tglx@timesys.com, mingo@elte.hu, johnstul@us.ibm.com,
	akpm@osdl.org, shill@free.fr
Subject: Re: One-shot high-resolution POSIX timer periodically late
Date: Thu, 01 Feb 2007 11:18:04 +0100	[thread overview]
Message-ID: <45C1BE5C.9050001@free.fr> (raw)
In-Reply-To: <fa.Id9oufyELrVbe5Wb8SRakwC0V50@ifi.uio.no>

[ Same player shoot again. Fix address. ]

Ingo Molnar wrote:

> John wrote:
> 
>> John Stultz wrote:
>>
>>> Also do check the -rt tree as Ingo suggested. I mis-read your earlier
>>> email and thought you were running it.
>>
>> I've been pulling my hair over a related issue for the past two days.
>>
>> (I think I may be tickling a -hrt bug...)
>>
>> I'm working with 2.6.18.6 + patch-2.6.18-rt7
> 
> 2.6.18-rt7 is pretty old, do you see the problem in 2.6.20-rc6-rt5 too?

Ingo, Thomas,

I cannot reproduce in 2.6.20-rc6-rt6, but it is not strictly an
apples-to-apples comparison because I get a tsc clocksource in
2.6.20-rc6-rt6, and an acpi_pm clocksource in 2.6.18.6-rt7.

Here are the relevant parts of my boot messages:

Linux version 2.6.18.6-rt7
ACPI: PM-Timer IO Port: 0x4008
Clock event device pit configured with caps set: 07
Time: acpi_pm clocksource has been installed.
Clock event device pit configured with caps set: 08
Switched to high resolution mode on CPU 0

Linux version 2.6.20-rc6-rt6
ACPI: PM-Timer IO Port: 0x4008
Time: tsc clocksource has been installed.

(pit and acpi_pm have disappeared from 2.6.20-rc6-rt6)

The -rt patch set looks great, but I am somewhat hesitant to use it. It
seems it is only updated for the latest kernel version available. Or am
I mistaken? In other words, once 2.6.20 is released, and work starts on
2.6.21, if a bug is discovered in -rt, the fix will not be back-ported
to the 2.6.20.x (and 2.6.19.x, and 2.6.18.x, etc) patch set?

NB: I do need high-resolution timers, but, at the same time, I'm not
very comfortable living on the bleeding edge, where new bugs and
regressions might not get caught in release candidates. (I work on an
industrial project where continuous operation is a requirement.)

Regards.


       reply	other threads:[~2007-02-01 10:18 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <fa.4zD54Ie6Ozt0P4YqQSicS+XzXGw@ifi.uio.no>
     [not found] ` <fa.G+/T32f2o1M3+YGLca/O8NaAQyY@ifi.uio.no>
     [not found]   ` <fa.6Ua8xjNfLKQEZZgDsoJgPMyww4g@ifi.uio.no>
     [not found]     ` <fa.yQlV+WU0TgrJTVqjopa01tgCnT0@ifi.uio.no>
     [not found]       ` <fa.ucVrLJ1Lh6FjdBHRglsIUc8/evk@ifi.uio.no>
     [not found]         ` <fa.Id9oufyELrVbe5Wb8SRakwC0V50@ifi.uio.no>
2007-02-01 10:18           ` John [this message]
2007-02-06 12:37             ` Ingo Molnar
2007-02-07 10:13               ` John
2007-02-05 16:37           ` John
2007-02-06  7:31             ` Peter Zijlstra
2007-02-07 10:25               ` John
2007-02-08 17:32                 ` Thomas Gleixner
2007-02-09 15:25                   ` John
2007-02-09 16:21                     ` Benedikt Spranger
2007-02-09 16:43                     ` Thomas Gleixner
     [not found] <fa.mtUvfgenNQkCc8835prYbwyiPQs@ifi.uio.no>
     [not found] ` <fa.lwkMc548uRMcUjd9KZ2pC1DMKT4@ifi.uio.no>
     [not found]   ` <fa.dTtI0ctv1nu+tCWiK6jGPnrX69k@ifi.uio.no>
     [not found]     ` <fa.CMU3scpnLxfHVWRFPcmfRl2CjhA@ifi.uio.no>
2007-01-30 17:38       ` John
2007-01-30 20:25         ` Ingo Molnar
     [not found] <fa.NwnlFyMPfa3XG6my3HKGWnCW3x4@ifi.uio.no>
     [not found] ` <fa.Ji4GnAbBF2FR5JbSxvxn2haJZIk@ifi.uio.no>
2007-01-25  9:59   ` John
2007-01-25 22:19     ` john stultz
     [not found]   ` <fa.8TBiwbgs8B881k+3X+IlFjhqpLI@ifi.uio.no>
2007-01-25 12:03     ` John
     [not found] <45B729AF.4030701@privacy.net>
2007-01-24 19:02 ` john stultz
2007-01-24 20:09   ` Ingo Molnar

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=45C1BE5C.9050001@free.fr \
    --to=shill@free.fr \
    --cc=akpm@osdl.org \
    --cc=johnstul@us.ibm.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mingo@elte.hu \
    --cc=tglx@timesys.com \
    --subject='Re: One-shot high-resolution POSIX timer periodically late' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).