Messages in this thread | | | Subject | Re: [linux-audio-dev] Re: [announce] [patch] Voluntary Kernel Preemption Patch | From | Lee Revell <> | Date | Tue, 20 Jul 2004 23:27:48 -0400 |
| |
On Mon, 2004-07-19 at 06:29, Ingo Molnar wrote: > * Andrew Morton <akpm@osdl.org> wrote: > > > > Should I try ext3? > > > > ext3 is certainly better than that, but still has a couple of > > potential problem spots. ext2 is probably the best at this time. > > with the voluntary-preempt patch applied ext3 is below ~500 usecs for > all things i tried on a 2GHz CPU. Without the patch i can trigger > latencies up to milliseconds (even with CONFIG_PREEMPT) by triggering a > bigger commit stream via some large file write or a cached du / causing > a stream of atime updates. (I very much suspect that all other > journalled filesystems have similar problems and they'll need > measurements and fixing just like ext3 does.) > > another bigger problem area is the VM - see my patch for details. > pagetable zapping and page reclaim are both problematic and need fixups > even under CONFIG_PREEMPT. Doing a simple 'make -j' kernel build that > hits swap triggers these easily. (after applying my patch the latencies > go below 1msec even with a 'make -j' overload.) >
I discovered I can reliably produce a large XRUN by toggling Caps Lock, Scroll Lock, or Num Lock. This is with 2.6.8-rc1-mm1 + voluntary preempt (I modified the patch by hand to apply on this kernel, as 2.6.8-rc2 disables my network card). Here is the XRUN trace.
ALSA /home/rlrevell/cvs/alsa-driver/alsa-kernel/core/pcm_lib.c:169: XRUN: pcmC0D0p [<c01066f7>] dump_stack+0x17/0x20 [<de952477>] snd_pcm_period_elapsed+0x2c7/0x400 [snd_pcm] [<de962477>] snd_emu10k1_interrupt+0x337/0x3c0 [snd_emu10k1] [<c0107913>] handle_IRQ_event+0x33/0x60 [<c0107c55>] do_IRQ+0xa5/0x170 [<c01062b8>] common_interrupt+0x18/0x20 [<c01d3f7f>] __delay+0xf/0x20 [<c021881a>] atkbd_sendbyte+0x5a/0xa0 [<c0218a35>] atkbd_command+0x1d5/0x200 [<c0218bcb>] atkbd_event+0x16b/0x200 [<c0215a95>] input_event+0x115/0x3d0 [<c01ecaeb>] kbd_bh+0xbb/0x160 [<c011a554>] tasklet_action+0x44/0x70 [<c011a303>] __do_softirq+0x83/0x90 [<c011a345>] do_softirq+0x35/0x40 [<c0107cc5>] do_IRQ+0x115/0x170 [<c01062b8>] common_interrupt+0x18/0x20 [<c014b95e>] sys_read+0x2e/0x50 [<c0106097>] syscall_call+0x7/0xb
Lee
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |