From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <52A05E08.10105@xenomai.org> Date: Thu, 05 Dec 2013 12:05:44 +0100 From: Philippe Gerum MIME-Version: 1.0 References: <40A5BE95-8E78-4CD6-81D2-C97AA7A58FBB@open.ac.uk> <529DCF2F.1070702@xenomai.org> <1507DF58-4A8D-42E0-92B8-4A9EAB4289E3@open.ac.uk> <529DDB58.3090709@xenomai.org> <5B55252A-19D2-4A0D-82BE-FC77BFA6AEE1@open.ac.uk> <529DFEC3.1050106@xenomai.org> <90F2A7A6-5B5E-4A25-8D9D-3D50D0EC0826@open.ac.uk> <529E2801.5060505@xenomai.org> <529EEB7C.4090308@xenomai.org> <529EED06.4010108@xenomai.org> <529EF58A.8030003@xenomai.org> <529EF680.1040108@xenomai.org> <529EF89E.6000302@xenomai.org> <529EFB3D.6090900@xenomai.org> <529F03FC.8040409@xenomai.org> <529F04DD.2070201@xenomai.org> <529F0C48.20705@xenomai.org> <529F0DBC.9080905@xenomai.org> <529F13A1.5070403@xenomai.org> <529F1913.4030604@xenomai.org> <529F1974.60900@xenomai.org> <529F2BED.2030403@xenomai.org> <529F5254.8060501@xenomai.org> <529F69AD.6060003@xenomai.org> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Xenomai] latency spikes under load List-Id: Discussions about the Xenomai project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Kurijn Buys Cc: "Xenomai@xenomai.org" On 12/05/2013 11:28 AM, Kurijn Buys wrote: > > Op 5-dec.-2013, om 00:44 heeft Kurijn Buys het volgende geschreven: > >> >> 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 latency test results in a worst value of 52us (no idea if this is normal, the lat max globally stays between 10 and 30us), but I have no higher pikes under load in each case... >> The other test I mentioned before still has a few measurements that occur at 10us in stead of 1000us... maybe it's an issue with this test... >> >> I have the same oddity as the other time I installed a 3.8 kernel on Ubuntu 10.04: >> -the /proc/ipipe files don't look how they should I guess. The Linux file is full of lines with "__ipipe_do_IRQ" and near the end a line with "__ipipe_do_critical_sync"... >> -the version file only states "1" Which is expected, the ipipe now reports its core release number. It looks like we forgot to bump it a couple of times though. >> -the xenomai file mainly has lines with "..." and also this critical sync line near the end. >> >> Also, I tried to enable the ipipe tracer but without the "tracing on boot" option, but I can't get it to work now. When I do "echo < 1 /proc/ipipe/trace/enable" (as root), the flag stays on 0. and the frozen file remains empty. > You likely mean: # echo 1 > /proc/ipipe/trace/enable > For some unknown reason, now the tracer works (I didn't even do a reboot en the mean time), and now I have difficulties setting trace/enable to 0. > > Another latency test had a pike of 62us (but pikes are very rare now, and not dependent on load anymore), which seems related to the ipipe frozen line: > -56! 44.220 __ipipe_spin_lock_irqsave+0x5 (mask_and_ack_8259A+0x22) > Accessing the legacy 8259 PIC is slow. # cat /proc/interrupt ? -- Philippe.