On Mon, 4 Apr 2005, kus Kusche Klaus wrote:
> I asked our hardware team. The hardware has two devices which are
> in use and capable of busmaster/DMA transfers:
> The intel e100 ethernet controller and the intel PIIX4 USB
> controller.
> The IDE interface is also a busmaster, but there are only
* kus Kusche Klaus <[EMAIL PROTECTED]> wrote:
> Moreover, we know from experience that the "WBINDV" instruction (Write
> back and invalidate CPU cache) can cause such latencies.
>
> Does this instruction occur anywhere in Linux?
yes, they rarely occur when MTRR's are set (and some drivers like
> * kus Kusche Klaus <[EMAIL PROTECTED]> wrote:
> >IRQ 7-724 0d..11us : end_8259A_irq (do_hardirq)
> >IRQ 7-724 0d..11us!: enable_8259A_irq (do_hardirq)
> >IRQ 7-724 0d... 832us : do_hardirq (do_irqd)
> >IRQ 7-724 0d... 833us : trace_irqs_on (do_hardirq)
>
> >
On Fri, 1 Apr 2005, kus Kusche Klaus wrote:
> > The biggest advantage would come from using a bottom-half
> > handler to do
> > most of the work. Right now the uhci-hcd driver does
> > everything in its
> > interrupt handler. This would certainly help IRQ latency; it
> > might not
> > affe
* kus Kusche Klaus <[EMAIL PROTECTED]> wrote:
>IRQ 7-724 0d..11us : end_8259A_irq (do_hardirq)
>IRQ 7-724 0d..11us!: enable_8259A_irq (do_hardirq)
>IRQ 7-724 0d... 832us : do_hardirq (do_irqd)
>IRQ 7-724 0d... 833us : trace_irqs_on (do_hardirq)
> mmap-1000
> > Even when the errors described in my previous mail does not occur,
> > massive USB stick transfers cause latencies of 1 to 2 milliseconds,
> > which is way too much for realtime control systems.
>
> do these occur under PREEMPT_RT? If yes, do you get any
> useful trace if
> you enable all
> > > The latencies are almost certainly caused by the USB host
> controller
> > > driver. I'm planning improvements to uhci-hcd which should
> > > help reduce
> > > the latency, but it will still be on the large side. And I
> > > won't have
> > > time to write the changes to the driver for
On Thu, 31 Mar 2005, kus Kusche Klaus wrote:
> > The latencies are almost certainly caused by the USB host controller
> > driver. I'm planning improvements to uhci-hcd which should
> > help reduce
> > the latency, but it will still be on the large side. And I
> > won't have
> > time to writ
> I couldn't find that previous email in the MARC archives.
>
> Regardless, you'd have to provide a small bit of information about
> your hardware configuration. What device speed: full or high?
> What controller: EHCI, OHCI, UHCI, something else? Which driver
> for the stick: usb-storage, or
* kus Kusche Klaus <[EMAIL PROTECTED]> wrote:
> I'm performing realtime latency tests (for details about the hardware
> and software, see my mail "[BUG] 2.6.11: Random SCSI/USB errors when
> reading from USB memory stick" erlier today).
>
> Even when the errors described in my previous mail do
> The latencies are almost certainly caused by the USB host controller
> driver. I'm planning improvements to uhci-hcd which should
> help reduce
> the latency, but it will still be on the large side. And I
> won't have
> time to write the changes to the driver for several months.
Any numbe
On Wed, 2005-03-30 at 17:40 -0800, David Brownell wrote:
> This all seems off-topic for latency though. :)
>
Disagree, in the bug reports I saw from JACK users the symptoms are
exactly the same as a kernel latency problem. The only clear hint that
it's something else is that the RT kernel and m
On Wednesday 30 March 2005 5:32 pm, Lee Revell wrote:
> On Wed, 2005-03-30 at 17:28 -0800, David Brownell wrote:
> > On Wednesday 30 March 2005 4:51 pm, Lee Revell wrote:
> > >
> > > This is the exact configuration of one of the users who reported the
> > > problem on LAU. Got a pointer to the pa
On Wed, 2005-03-30 at 17:28 -0800, David Brownell wrote:
> This is what Greg just posted (and Linus merged into BK, so it'll be
> in BK snapshots starting tomorrow):
>
> http://marc.theaimsgroup.com/?l=linux-usb-devel&m=111221966815043&w=2
Wow, just checked my mail and there were at least 5 thr
> > Please don't assume everyone subscribes to LKML, or that
> > everything crafted to be threaded more-or-less-correctly
> > was really crafted with any kind of "reply" command. :)
>
> Um, that's exactly why reply-to-all should be used,
There you go, assuming that there was a message to which
On Wed, 2005-03-30 at 17:28 -0800, David Brownell wrote:
> On Wednesday 30 March 2005 4:51 pm, Lee Revell wrote:
> > [cc list restored]
>
> Thanks, I never had one to start with ... :)
>
>
Thank you. Sorry for the tone of my reply...
> > On Wed, 2005-03-30 at 14:57 -0800, David Brownell wrote
On Wednesday 30 March 2005 4:51 pm, Lee Revell wrote:
> [cc list restored]
Thanks, I never had one to start with ... :)
> On Wed, 2005-03-30 at 14:57 -0800, David Brownell wrote:
> > Quoth [EMAIL PROTECTED]:
> > > I think this is connected to a problem people have been reporting on the
> > > Lin
On Wed, 2005-03-30 at 17:13 -0800, David Brownell wrote:
> On Wednesday 30 March 2005 4:43 pm, Lee Revell wrote:
> > On Wed, 2005-03-30 at 14:57 -0800, David Brownell wrote:
> > > Quoth [EMAIL PROTECTED]:
> > > > I think this is connected to a problem people have been reporting on the
> > > > Linux
On Wednesday 30 March 2005 4:43 pm, Lee Revell wrote:
> On Wed, 2005-03-30 at 14:57 -0800, David Brownell wrote:
> > Quoth [EMAIL PROTECTED]:
> > > I think this is connected to a problem people have been reporting on the
> > > Linux audio lists. With some USB chipsets, USB audio interfaces just
>
[cc list restored]
On Wed, 2005-03-30 at 14:57 -0800, David Brownell wrote:
> Quoth [EMAIL PROTECTED]:
> > I think this is connected to a problem people have been reporting on the
> > Linux audio lists. With some USB chipsets, USB audio interfaces just
> > don't work. There are dropouts even at
On Wed, 2005-03-30 at 14:57 -0800, David Brownell wrote:
> Quoth [EMAIL PROTECTED]:
> > I think this is connected to a problem people have been reporting on the
> > Linux audio lists. With some USB chipsets, USB audio interfaces just
> > don't work. There are dropouts even at very high latencies.
On Wed, 2005-03-30 at 10:55 -0500, Alan Stern wrote:
> On Wed, 30 Mar 2005, kus Kusche Klaus wrote:
>
> > I'm performing realtime latency tests (for details about the hardware
> > and software, see my mail "[BUG] 2.6.11: Random SCSI/USB errors when
> > reading from USB memory stick" erlier today).
On Wed, 30 Mar 2005, kus Kusche Klaus wrote:
> I'm performing realtime latency tests (for details about the hardware
> and software, see my mail "[BUG] 2.6.11: Random SCSI/USB errors when
> reading from USB memory stick" erlier today).
>
> Even when the errors described in my previous mail does n
I'm performing realtime latency tests (for details about the hardware
and software, see my mail "[BUG] 2.6.11: Random SCSI/USB errors when
reading from USB memory stick" erlier today).
Even when the errors described in my previous mail does not occur,
massive USB stick transfers cause latencies of
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