From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <4CC5F612.8040508@domain.hid> Date: Mon, 25 Oct 2010 23:26:42 +0200 From: Jan Kiszka MIME-Version: 1.0 References: <4CC20AD2.4060501@domain.hid> <4CC44C02.4050003@domain.hid> <4CC5603E.1090707@domain.hid> <4CC566A2.2000702@domain.hid> <4CC5C93E.70503@domain.hid> <4CC5DD1F.4090405@domain.hid> <1288041712.26618.189.camel@domain.hid> In-Reply-To: <1288041712.26618.189.camel@domain.hid> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig6987D8C713068FCBD775E599" Sender: jan.kiszka@domain.hid Subject: Re: [Xenomai-help] Slow hard drive access in xenomai List-Id: Help regarding installation and common use of Xenomai List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Philippe Gerum Cc: xenomai@xenomai.org, Peter Pastor This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig6987D8C713068FCBD775E599 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Am 25.10.2010 23:21, Philippe Gerum wrote: > On Mon, 2010-10-25 at 21:40 +0200, Jan Kiszka wrote: >> Am 25.10.2010 21:03, Peter Pastor wrote: >>> Hey Jan, >>> >>> I did not apply any ubuntu patch for kernel 2.6.35 (since I do not ha= ve >>> one). Also, good to know that I should not use xenomai patches toget= her >>> with ubuntu patches. >>> >>> Anyway, the problem occurred as well with the kernel 2.6.35 (see atta= ched >>> dmesg_bad_2.6.35) >>> I also attached the config. >>> >> >> ... >> >>> [ 5751.714643] irq 16: nobody cared (try booting with the "irqpoll" o= ption) >>> [ 5751.714649] Pid: 0, comm: swapper Tainted: P 2.6.35-ipi= pe-2.5.4-slim #2 >>> [ 5751.714653] Call Trace: >>> [ 5751.714655] [] __report_bad_irq+0x26/0xa= 0 >>> [ 5751.714668] [] note_interrupt+0x18c/0x1d0 >>> [ 5751.714672] [] handle_fasteoi_irq+0xcd/0x100 >>> [ 5751.714677] [] handle_irq+0x1d/0x30 >>> [ 5751.714681] [] do_IRQ+0x70/0x100 >>> [ 5751.714685] [] __ipipe_sync_stage+0x207/0x20d >>> [ 5751.714689] [] ? do_IRQ+0x0/0x100 >>> [ 5751.714692] [] ? __xirq_end+0x0/0x9c >>> [ 5751.714696] [] ? do_IRQ+0x0/0x100 >>> [ 5751.714700] [] __ipipe_walk_pipeline+0x113/0x12= 0 >>> [ 5751.714706] [] __ipipe_handle_irq+0x124/0x310 >>> [ 5751.714708] [] ? __ipipe_ack_fasteoi_irq+0x0/0x= 10 >>> [ 5751.714712] [] common_interrupt+0x13/0x2c >>> [ 5751.714713] [] ? __ipipe_halt_root+0x26/= 0x40 >>> [ 5751.714718] [] ? atomic_notifier_call_chain+0x1= 1/0x20 >>> [ 5751.714722] [] default_idle+0x45/0x50 >>> [ 5751.714725] [] cpu_idle+0x7a/0xd0 >>> [ 5751.714728] [] start_secondary+0x1c1/0x1c5 >>> [ 5751.714730] handlers: >>> [ 5751.714730] [] (usb_hcd_irq+0x0/0xb0) >>> [ 5751.714735] [] (mpt_interrupt+0x0/0xa00 [mptbase= ]) >>> [ 5751.714747] Disabling IRQ #16 >> >> I'm not yet sure, but a first thought: We have a shared fasteoi IRQ >> here, and we are on SMP. Compared to vanilla, the fasteoi flow of ipip= e >> looks so much different to me ATM that I tend to believe two cores end= >> up having this IRQ queued at the same time. One runs first and handles= >> all triggers, the second bails out like above. >> >> Philippe, we _end_ fasteoi in the ipipe ack path. Do we mask them prio= r >> to this? What prevents a second IRQ arriving after this early eoi? >=20 > All fasteoi handlers are supposed to mask+ack when the pipeline is > enabled,=20 What am I missing? The code I was looking at (__ipipe_ack_fasteoi) just does a regular eoi at chip level. > to avoid interrupt storm due to the deferral we may introduce > in the irq delivery. I do see this in the regular ioapic chip > descriptor, but this is lacking with interrupt remap. I guess we could > have a problem with Intel IOMMUs. IOMMUs should blow up the system anyway once a PCI driver is used in the RT domain (DMA remapping involved Linux locks and may even allocate memory). Guess we should add a !IPIPE to their Kconfig entries. Jan --------------enig6987D8C713068FCBD775E599 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.15 (GNU/Linux) Comment: Using GnuPG with SUSE - http://enigmail.mozdev.org/ iEYEARECAAYFAkzF9hIACgkQitSsb3rl5xReSQCgylK00Gqcr+qzhIa14EEKmZmh BmgAn2zzaetAdI7qGmntWm4wqajvYxVH =tlef -----END PGP SIGNATURE----- --------------enig6987D8C713068FCBD775E599--