From: Philippe Elie <phil.el@wanadoo.fr>
To: Andrew Morton <akpm@osdl.org>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH] nmi_watchdog=2 and P4-HT
Date: Thu, 4 Mar 2004 08:20:30 +0000 [thread overview]
Message-ID: <20040304082030.GD683@zaniah> (raw)
In-Reply-To: <20040303223235.177685dd.akpm@osdl.org>
On Wed, 03 Mar 2004 at 22:32 +0000, Andrew Morton wrote:
> Philippe Elie <phil.el@wanadoo.fr> wrote:
> >
> >
> > What do you think about the feature "the performance doesn't increment
> > counter in hlt mode".
>
> That sounds OK. If the CPU halts with local interrupts disabled (is this
> possible?) then I assume it'll never come back. But this possibility isn't
> worth worrying about, surely.
>
> Can we scale the performance counter multiplier down a bit? 1000 NMIs per
> second sounds excessive.
yups and on HT it's 2000 NMI on one physical processor
I think to something like this, it's just a quick draw so you get the
idea. it's the less bad patch I can provide, get a look at the apic.c
chunk, I needed to remove the check_nmi_watchdog(); test for UP else
this test will complete in 10 seconds. Look like ugly but anyway on
SMP and with nmi_watchdog=2 we never call check_nmi_watchdog() and
I think the purpose of check_nmi_watchdog() is to test IO apic not
local apic after all if a local apic is up it must be sane ?
Phil sleeping
--- linux-2.6/arch/i386/kernel/nmi.c~ 2004-03-04 08:05:48.000000000 +0000
+++ linux-2.6/arch/i386/kernel/nmi.c 2004-03-04 08:05:55.000000000 +0000
@@ -347,6 +347,8 @@ static int setup_p4_watchdog(void)
void setup_apic_nmi_watchdog (void)
{
+ nmi_hz = 1;
+
switch (boot_cpu_data.x86_vendor) {
case X86_VENDOR_AMD:
if (boot_cpu_data.x86 != 6 && boot_cpu_data.x86 != 15)
--- linux-2.6.orig/arch/i386/kernel/apic.c 2004-03-04 05:05:19.000000000 +0000
+++ linux-2.6/arch/i386/kernel/apic.c 2004-03-04 07:44:50.000000000 +0000
@@ -1182,9 +1182,6 @@ int __init APIC_init_uniprocessor (void)
phys_cpu_present_map = physid_mask_of_physid(boot_cpu_physical_apicid);
setup_local_APIC();
-
- if (nmi_watchdog == NMI_LOCAL_APIC)
- check_nmi_watchdog();
#ifdef CONFIG_X86_IO_APIC
if (smp_found_config)
if (!skip_ioapic_setup && nr_ioapics)
next prev parent reply other threads:[~2004-03-04 7:20 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-03-04 5:42 [PATCH] nmi_watchdog=2 and P4-HT Philippe Elie
2004-03-04 5:30 ` Andrew Morton
2004-03-04 7:26 ` Philippe Elie
2004-03-04 6:32 ` Andrew Morton
2004-03-04 8:20 ` Philippe Elie [this message]
2004-03-05 5:42 ` [PATCH] set nmi_hz to 1 with nmi_watchdog=2 and SMP Philippe Elie
2004-03-04 8:04 ` [PATCH] nmi_watchdog=2 and P4-HT Philippe Elie
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