[Linux-ia64] [patch] 2.4 arch/ia64/kernel/smpboot.c

[Linux-ia64] [patch] 2.4 arch/ia64/kernel/smpboot.c

[Jes Sorensen]

Hi,

A small patch for 2.4 that stops the kernel from trying to syncrhonize
ITC clocks between CPUs if we know that the ITC isn't synchronized
across the backplane.

The patch is relative to 2.4.21-pre5-bjorn, but I believe it should
apply directly to 2.5.x as well.

Cheers,
Jes

--- ../linux-2.4.20-021210/arch/ia64/kernel/smpboot.c	Tue Mar 11 11:23:49 2003
+++ arch/ia64/kernel/smpboot.c	Wed Mar 26 06:19:17 2003
@@ -334,12 +334,15 @@
 
 	smp_setup_percpu_timer();
 
-	/*
-	 * Synchronize the ITC with the BP
-	 */
-	Dprintk("Going to syncup ITC with BP.\n");
+	if (!(sal_platform_features & IA64_SAL_PLATFORM_FEATURE_ITC_DRIFT)) {
+		/*
+		 * Synchronize the ITC with the BP
+		 */
+		Dprintk("Going to syncup ITC with BP.\n");
+
+		ia64_sync_itc(0);
+	}
 
-	ia64_sync_itc(0);
 	/*
 	 * Get our bogomips.
 	 */

Re: [Linux-ia64] [patch] 2.4 arch/ia64/kernel/smpboot.c

[David Mosberger]

>>>>> On Wed, 26 Mar 2003 11:27:55 -0500, Jes Sorensen <jes@wildopensource.com> said:

  Jes> A small patch for 2.4 that stops the kernel from trying to syncrhonize
  Jes> ITC clocks between CPUs if we know that the ITC isn't synchronized
  Jes> across the backplane.

  Jes> The patch is relative to 2.4.21-pre5-bjorn, but I believe it should
  Jes> apply directly to 2.5.x as well.

Applied.  In the future, please send patches that apply with patch
-p1.  Also, I think you'll want to add similar code to the
gettimeofday() interpolation (and don't forget about the light-weight
version of gettimeofday()).

Thanks,

	--david

Re: [Linux-ia64] [patch] 2.4 arch/ia64/kernel/smpboot.c

[Bjorn Helgaas]

On Wednesday 26 March 2003 9:27 am, Jes Sorensen wrote:
> A small patch for 2.4 that stops the kernel from trying to syncrhonize
> ITC clocks between CPUs if we know that the ITC isn't synchronized
> across the backplane.
> 
> The patch is relative to 2.4.21-pre5-bjorn, but I believe it should
> apply directly to 2.5.x as well.

I applied this to 2.4.