From: Ingo Molnar <mingo@elte.hu>
To: "Bill Rugolsky Jr." <brugolsky@telemetry-investments.com>,
Andi Kleen <ak@suse.de>, Jeff Garzik <jeff@garzik.org>,
Lee Revell <rlrevell@joe-job.com>,
Jason Baron <jbaron@redhat.com>,
linux-kernel@vger.kernel.org, john stultz <johnstul@us.ibm.com>
Subject: Re: libata/sata_nv latency on NVIDIA CK804 [was Re: AMD64 X2 lost ticks on PM timer]
Date: Wed, 15 Mar 2006 22:50:20 +0100 [thread overview]
Message-ID: <20060315215020.GA18241@elte.hu> (raw)
In-Reply-To: <20060315213638.GA17817@ti64.telemetry-investments.com>
* Bill Rugolsky Jr. <brugolsky@telemetry-investments.com> wrote:
> <...>-2913 0d.h. 8us : raise_softirq_irqoff (blk_complete_request)
> <...>-2913 0d.h. 8us : __ata_qc_complete (ata_qc_complete)
> <...>-2913 0d.h. 9us : ata_host_intr (nv_interrupt)
> <...>-2913 0d.h. 9us!: ata_bmdma_status (ata_host_intr)
> <...>-2913 0d.h. 16641us : nv_check_hotplug_ck804 (nv_interrupt)
> <...>-2913 0d.h. 16642us : _spin_unlock_irqrestore (nv_interrupt)
> <...>-2913 0d.h. 16642us : smp_apic_timer_interrupt (apic_timer_interrupt)
> <...>-2913 0d.h. 16642us : exit_idle (smp_apic_timer_interrupt)
ouch. The codepath in question (ata_host_intr()) doesnt seem to have any
loop that could take 16.6 msecs (!). This very much looks like some
hardware-triggered delay - some really screwed up DMA prioritization
perhaps, starving the host CPU for 16.6 msecs? But what DMA takes 16.6
msecs? That's enough time to transfer dozens of megabytes of data on a
midrange system.
Ingo
next prev parent reply other threads:[~2006-03-15 21:53 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-02-27 21:22 AMD64 X2 lost ticks on PM timer bubshait
2006-02-27 22:21 ` Bill Rugolsky Jr.
2006-02-27 22:47 ` Jason Baron
2006-02-28 7:41 ` Abdulla Bubshait
2006-02-28 22:00 ` Bill Rugolsky Jr.
2006-02-28 23:53 ` Andi Kleen
2006-03-01 14:46 ` Bill Rugolsky Jr.
2006-03-01 14:56 ` Andi Kleen
2006-03-01 15:43 ` Bill Rugolsky Jr.
2006-03-01 15:47 ` Andi Kleen
2006-03-01 18:07 ` Bill Rugolsky Jr.
2006-03-01 18:29 ` Andi Kleen
2006-03-01 19:16 ` Lee Revell
2006-03-03 19:18 ` Bill Rugolsky Jr.
2006-03-03 21:26 ` Lee Revell
2006-03-03 22:09 ` Jeff Garzik
2006-03-03 23:43 ` Bill Rugolsky Jr.
2006-03-03 23:46 ` Jeff Garzik
2006-03-03 23:49 ` Lee Revell
2006-03-04 0:08 ` Andi Kleen
2006-03-04 0:07 ` Andi Kleen
[not found] ` <20060315213638.GA17817@ti64.telemetry-investments.com>
2006-03-15 21:45 ` libata/sata_nv latency on NVIDIA CK804 [was Re: AMD64 X2 lost ticks on PM timer] Lee Revell
2006-03-15 21:58 ` Ingo Molnar
2006-03-15 22:00 ` Ingo Molnar
2006-03-15 22:25 ` Jeff Garzik
2006-03-16 15:13 ` Alan Cox
2006-03-16 16:57 ` Bill Rugolsky Jr.
2006-03-22 16:09 ` Andi Kleen
2006-03-22 18:39 ` Bill Rugolsky Jr.
2006-03-22 23:07 ` Bill Rugolsky Jr.
2006-03-15 22:22 ` Jeff Garzik
2006-03-15 22:24 ` Ingo Molnar
2006-03-15 22:36 ` Bill Rugolsky Jr.
2006-03-15 22:46 ` Ingo Molnar
2006-03-15 22:48 ` Jeff Garzik
2006-03-15 23:31 ` Lee Revell
2006-03-15 21:50 ` Ingo Molnar [this message]
2006-03-15 22:11 ` Ingo Molnar
2006-03-15 22:33 ` Jeff Garzik
2006-03-15 22:44 ` Ingo Molnar
2006-03-15 22:50 ` Jeff Garzik
2006-03-15 23:14 ` Bill Rugolsky Jr.
2006-03-15 23:44 ` Lee Revell
[not found] ` <20060316002133.GE17817@ti64.telemetry-investments.com>
2006-03-16 0:48 ` Long latencies with MD RAID 1 [was Re: libata/sata_nv latency on NVIDIA CK804 ] Lee Revell
2006-03-16 3:15 ` libata/sata_nv latency on NVIDIA CK804 [was Re: AMD64 X2 lost ticks on PM timer] Bill Rugolsky Jr.
2006-03-16 4:20 ` Lee Revell
2006-03-16 9:18 ` Ingo Molnar
2006-03-16 14:42 ` Gabor Gombas
2006-03-16 0:01 ` Lee Revell
2006-03-16 0:14 ` Jeff Garzik
2006-03-15 22:30 ` Jeff Garzik
2006-03-15 22:36 ` Ingo Molnar
2006-03-15 22:04 ` [patch] latency-tracing-v2.6.16.patch Ingo Molnar
2006-03-15 22:32 ` Bill Rugolsky Jr.
2006-03-16 9:18 ` Ingo Molnar
2006-03-04 12:06 ` AMD64 X2 lost ticks on PM timer Martin Schlemmer
2006-03-05 7:07 ` Alexander Samad
2006-03-02 15:47 ` Gabor Gombas
2006-02-28 21:17 ` Abdulla Bubshait
-- strict thread matches above, loose matches on Subject: below --
2006-03-16 0:33 libata/sata_nv latency on NVIDIA CK804 [was Re: AMD64 X2 lost ticks on PM timer] Allen Martin
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