Re: [patch] voluntary-preempt-2.6.8-rc3-O4

Lee Revell
2004-08-10T02:06:14Z

On Mon, 2004-08-09 at 13:02, Florian Schmidt wrote:
> On Mon, 9 Aug 2004 15:05:58 +0200
> Ingo Molnar <mingo@elte.hu> wrote:
>
> >
> > * Ingo Molnar <mingo@elte.hu> wrote:
> >
> > > (the APIC bug has not been found yet so either turn off all APIC
> > > options in .config or use noapic if you intend to use
> > > voluntary_preempt=3.)
> >
> > but it would be nice if those experiencing APIC lockups could test the
> > following: does the lockup still occur with -O4 if
> > kernel_preemption=0?(while keeping voluntary_preemption=3)
>
> I don't use APIC, since it never worked good for me.. But i wanted to
> report that the mlockall latency still seems to be there.. I can easily
> trigger it with mlockall'ing > ~10000kb. Need to recompile with the
> preempt-timing patch, but here's an xrun trace that happened when
> mlockall'ing 20000kb:
>

Same results here, the mlockall problem is not fixed by -O4:

ALSA /home/rlrevell/cvs/alsa/alsa-driver/alsa-kernel/core/pcm_lib.c:139:
XRUN: pcmC0D2c
[<c0106717>] dump_stack+0x17/0x20
[<de93664b>] snd_pcm_period_elapsed+0x27b/0x3e0 [snd_pcm]
[<de9571d1>] snd_emu10k1_interrupt+0xd1/0x3c0 [snd_emu10k1]
[<c011a7d3>] generic_handle_IRQ_event+0x33/0x60
[<c01079c2>] do_IRQ+0xb2/0x180
[<c01062d8>] common_interrupt+0x18/0x20
[<c013e2ee>] do_anonymous_page+0x7e/0x190
[<c013e44e>] do_no_page+0x4e/0x310
[<c013e8d1>] handle_mm_fault+0xc1/0x170
[<c013d2a0>] get_user_pages+0x130/0x3b0
[<c013ea28>] make_pages_present+0x68/0x90
[<c01401d8>] do_mmap_pgoff+0x3f8/0x640
[<c010b656>] sys_mmap2+0x76/0xb0
[<c01060b7>] syscall_call+0x7/0xb
(jackd/778): 10984us non-preemptible critical section violated 1100 us
preempt threshold starting at kmap_atomic+0x10/0x60 and ending at
kunmap_atomic+0x8/0x20
[<c0106717>] dump_stack+0x17/0x20
[<c0113eec>] dec_preempt_count+0x3c/0x50
[<c0111ce8>] kunmap_atomic+0x8/0x20
[<c013e2fb>] do_anonymous_page+0x8b/0x190
[<c013e44e>] do_no_page+0x4e/0x310
[<c013e8d1>] handle_mm_fault+0xc1/0x170
[<c013d2a0>] get_user_pages+0x130/0x3b0
[<c013ea28>] make_pages_present+0x68/0x90
[<c01401d8>] do_mmap_pgoff+0x3f8/0x640
[<c010b656>] sys_mmap2+0x76/0xb0
[<c01060b7>] syscall_call+0x7/0xb

Lee