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From: Kurijn Buys <Kurijn.Buys@open.ac.uk>
To: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
Cc: Xenomai@xenomai.org
Subject: Re: [Xenomai] latency spikes under load
Date: Wed, 11 Dec 2013 14:23:38 +0000	[thread overview]
Message-ID: <4453D563-1D0B-4C5E-BCF1-3E2E8068B514@open.ac.uk> (raw)
In-Reply-To: <52A5E155.2040303@xenomai.org>


Op 9-dec.-2013, om 15:27 heeft Gilles Chanteperdrix het volgende geschreven:

> On 12/09/2013 04:19 PM, Kurijn Buys wrote:
>> Op 5-dec.-2013, om 11:09 heeft Gilles Chanteperdrix het volgende geschreven:
>>
>>> On 12/05/2013 01:44 AM, Kurijn Buys wrote:
>>>>
>>>> Op 4-dec.-2013, om 17:43 heeft Philippe Gerum het volgende geschreven:
>>>>
>>>>> On 12/04/2013 05:03 PM, Gilles Chanteperdrix wrote:
>>>>>> On 12/04/2013 02:19 PM, Philippe Gerum wrote:
>>>>>>> On 12/04/2013 01:00 PM, Gilles Chanteperdrix wrote:
>>>>>>>> Ok, could you push the branch somewhere so that I can try it?
>>>>>>>>
>>>>>>>
>>>>>>> testing/ipipe-3.8-i915-fix
>>>>>>
>>>>>> I could test it, I no longer get high latencies while moving a large
>>>>>> opengl window. So, it looks good.
>>>>
>>>> I've it running as well (with the priority coupling option disabled this time).
>>>
>>> The options I asked you to change were meant to eliminate any possible
>>> source for high latencies in case of bug. You can return to a normal
>>> configuration now: re-enable SMP or APIC if you prefer to remain in
>>> single processor mode, disable the I-pipe tracer if you want to avoid
>>> the overhead, and re-enable priority coupling if you prefer to use it.
>>
>> Re-enabling SMP is fine, but doesn't necessarily seem to improve the latency.
>> While I'm still having some small pikes, they keep below 60us, so that is fine to me.
>
> If your processor has hyper-threading, you may have much better results
> indeed in single processor mode, but enabling APIC and IO/APIC to avoid
> the spikes you got when using the legacy PIC.

I enabled APIC, and the latency peaks at 16us only now, and even less with load.
This also had an effect on my analogy problem, but not completely... I will start a new thread for that...

Thanks a lot already for resolving this issue!
]{urijn

-- The Open University is incorporated by Royal Charter (RC 000391), an exempt charity in England & Wales and a charity registered in Scotland (SC 038302).


  reply	other threads:[~2013-12-11 14:23 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-12-03 11:38 [Xenomai] latency spikes under load Kurijn Buys
2013-12-03 11:54 ` Gilles Chanteperdrix
2013-12-03 12:31 ` Gilles Chanteperdrix
2013-12-03 13:07   ` Kurijn Buys
2013-12-03 13:23     ` Gilles Chanteperdrix
2013-12-03 15:31       ` Kurijn Buys
2013-12-03 15:54         ` Gilles Chanteperdrix
2013-12-03 16:49           ` Kurijn Buys
2013-12-03 18:50             ` Gilles Chanteperdrix
2013-12-04  8:44               ` Philippe Gerum
2013-12-04  8:51                 ` Gilles Chanteperdrix
2013-12-04  9:27                   ` Philippe Gerum
2013-12-04  9:31                     ` Gilles Chanteperdrix
2013-12-04  9:40                       ` Philippe Gerum
2013-12-04  9:51                         ` Gilles Chanteperdrix
2013-12-04 10:29                           ` Philippe Gerum
2013-12-04 10:33                             ` Philippe Gerum
2013-12-04 11:04                               ` Philippe Gerum
2013-12-04 11:10                                 ` Gilles Chanteperdrix
2013-12-04 11:36                                   ` Philippe Gerum
2013-12-04 11:59                                     ` Philippe Gerum
2013-12-04 12:00                                       ` Gilles Chanteperdrix
2013-12-04 13:19                                         ` Philippe Gerum
2013-12-04 16:03                                           ` Gilles Chanteperdrix
2013-12-04 17:43                                             ` Philippe Gerum
2013-12-05  0:44                                               ` Kurijn Buys
2013-12-05 10:28                                                 ` Kurijn Buys
2013-12-05 11:05                                                   ` Philippe Gerum
2013-12-05 11:09                                                 ` Gilles Chanteperdrix
2013-12-09 15:19                                                   ` Kurijn Buys
2013-12-09 15:27                                                     ` Gilles Chanteperdrix
2013-12-11 14:23                                                       ` Kurijn Buys [this message]
2013-12-11 14:51                                                         ` Lennart Sorensen
2013-12-11 16:04                                                           ` Tobias Luksch
2013-12-11 17:21                                                             ` Gilles Chanteperdrix
2013-12-11 16:44                                                       ` [Xenomai] Analogy NI 6052E Kurijn Buys
2014-03-21 14:33                                                         ` Erhart Robert (CC-DA/ESR3)
2014-03-22 16:58                                                           ` Gilles Chanteperdrix

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