[RT] Compile error with certain IRQ debug config option combinations

2008-02-14 Thread kus Kusche Klaus
I'm using 2.6.24.2 with -rt1 applied (applies cleanly with some offsets) on x86. I've *not* configured PROVE_LOCKING (too expensive). However, I selected all the latency tracings, timings and histograms, among them CRITICAL_IRQSOFF_TIMING. This implicitly configures TRACE_IRQFLAGS. However, TRACE

RT 45-01: CF Card read: High latency?

2005-04-11 Thread kus Kusche Klaus
>From the three sources of multi-millisecond latency in my experiments (console messages to dead serial console, USB I/O, CF Card bulk read), I've analyzed one: The latency of around 70 milliseconds in low-priority RT processes when running a "dd if=/dev/hda of=/dev/null" in parallel (where hda i

BUG in RT 45-01 when RT program dumps core

2005-04-11 Thread kus Kusche Klaus
When a process running with RT priority dumps core, I get the following BUG: Apr 11 13:44:23 OF455 kern.err kernel: BUG: rtc2:833 RT task yield()-ing! Apr 11 13:44:23 OF455 kern.warn kernel: [] yield+0x61/0x70 (8) Apr 11 13:44:23 OF455 kern.warn kernel: [] coredump_wait+0x79/0xc0 (20) Apr 11 13:

RE: 2.6.11, USB: High latency?

2005-04-04 Thread kus Kusche Klaus
> * 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...

RE: 2.6.11, USB: High latency?

2005-04-01 Thread kus Kusche Klaus
> > 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

RE: 2.6.11, IDE: Strange scheduling behaviour: high-pri RT process not scheduled?

2005-04-01 Thread kus Kusche Klaus
> > The following tests are made with 'IRQ 8' at 95, rtc_wakeup > at 89(99): > > * Heavy mmap load, no oom: max jitter: 42.1% ( 51 usec) > > * Heavy mmap load, oom:max jitter: 11989.2% (14635 usec) > > (but still "missed irqs: 0", so IRQ 8 was also blocked for 14 ms) > > did you get

RE: 2.6.11, USB: High latency?

2005-03-31 Thread kus Kusche Klaus
> > > 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

RE: [BUG] 2.6.11: Random SCSI/USB errors when reading from USB memory stick

2005-03-31 Thread kus Kusche Klaus
> > > Latency is the subject of a separate email. Does this > > > increase in latency > > > occur only when you see the errors, or whenever you do a > large data > > > transfer? In fact, I would suspect the errors to _decrease_ > > > the latency > > > with respect to a normal transfer. > >

RE: 2.6.11, IDE: Strange scheduling behaviour: high-pri RT process not scheduled?

2005-03-31 Thread kus Kusche Klaus
> getting /dev/rtc handling right for latency measurement is > ... tricky. > The method i'm using under PREEMPT_RT is: > > chrt -f 84 -p `pidof 'IRQ 0'` > chrt -f 95 -p `pidof 'IRQ 8'` > ./rtc_wakeup -f 1024 -t 10 I tried it your way. First impressions with realtime-preempt-2.6.12-rc1-

RE: 2.6.11, USB: High latency?

2005-03-31 Thread kus Kusche Klaus
> 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

RE: [BUG] 2.6.11: Random SCSI/USB errors when reading from USB memory stick

2005-03-31 Thread kus Kusche Klaus
> Latency is the subject of a separate email. Does this > increase in latency > occur only when you see the errors, or whenever you do a large data > transfer? In fact, I would suspect the errors to _decrease_ > the latency > with respect to a normal transfer. I observe from <1 to 2 ms on s

RE: 2.6.11, USB: High latency?

2005-03-31 Thread kus Kusche Klaus
> 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

RE: 2.6.11, IDE: Strange scheduling behaviour: high-pri RT process not scheduled?

2005-03-31 Thread kus Kusche Klaus
> > The test system runs a 2.6.11 kernel (no SMP) on a Pentium3 500 MHz > > embedded hardware. > > which probably has memory bandwidth of at most a couple hundred MB/s, > which is really horrible by modern standards. It's my job to find out if linux can be used for control systems on this (and

RE: [patch] Real-Time Preemption, -RT-2.6.12-rc1-V0.7.41-25

2005-03-31 Thread kus Kusche Klaus
> i have released the -V0.7.41-25 Real-Time Preemption patch, > which can be > downloaded from the usual place: 1. Does not compile without RT_DEADLOCK_DETECT: kernel/rt.c: In function `change_owner': kernel/rt.c:556: error: structure has no member named `debug' kernel/rt.c: In function `pi_setp

2.6.11, USB: High latency?

2005-03-30 Thread kus Kusche Klaus
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

PREEMPT_RT: Undetected latencies?

2005-03-30 Thread kus Kusche Klaus
I'm experimenting with a realtime-preempt-2.6.12-rc1-V0.7.41-11 kernel, preemption fully enabled, and a small RTC test program (see my previous mail for details). If my program runs at rtprio 99, most of the time everything is fine: * My program records intervals of 122 +- 40 microseconds (which c

RE: 2.6.11, IDE: Strange scheduling behaviour: high-pri RT process not scheduled?

2005-03-30 Thread kus Kusche Klaus
> From: Bartlomiej Zolnierkiewicz [mailto:[EMAIL PROTECTED] > > On Wed, 30 Mar 2005 13:52:05 +0200, kus Kusche Klaus > <[EMAIL PROTECTED]> wrote: > > However, things break seriously when exercising the CF card > in parallel > > (e.g. with a dd if=/dev/hda

2.6.11, IDE: Strange scheduling behaviour: high-pri RT process not scheduled?

2005-03-30 Thread kus Kusche Klaus
I've written a small test program which enables periodic RTC interrupts at 8192 Hz and then goes into a loop reading /dev/rtc and collecting timing statistics (using the rdtscl macro). The program runs at highest realtime scheduling priority (99) with memory locked. In the loop, it doesn't do a

[BUG] 2.6.11: Random SCSI/USB errors when reading from USB memory stick

2005-03-30 Thread kus Kusche Klaus
When trying a "dd if=/dev/sda of=/dev/null" (where /dev/sda is an USB memory stick), this works fine for some seconds (and actually transfers data at around 700-1000 KB/s), but ends up with some I/O errors sooner or later, which cause the device to go offline (the stick must be replugged to make it