Re: [patch 4/4] powerpc 2.6.21-rt1: reduce scheduling latency by changing tlb flush size

At Mon, 14 May 2007 16:40:02 +0200, Arnd Bergmann wrote:

=20
On Monday 14 May 2007, Tsutomu OWA wrote:

quoted

--- linux-2.6.21-rt1/include/asm-powerpc/tlbflush.h=A0=A0=A0=A0=A02007-=

04-26 12:08:32.000000000 +0900

quoted

+++ rt/include/asm-powerpc/tlbflush.h=A0=A0=A02007-05-14 16:12:47.00000=

0000 +0900

quoted

@@ -25,7 +25,12 @@ struct mm_struct;

=A0#include <linux/percpu.h>
=A0#include <asm/page.h>
=A0
+#if defined(CONFIG_PPC_CELLEB) && defined(CONFIG_PREEMPT_RT)
+/* Since tlb flush takes long time on Celleb, reduce it to 1 when Cell=

eb && RT */

quoted

+#define PPC64_TLB_BATCH_NR 1

With this code, you get silent side-effects of enabling PPC_CELLEB
along with another platform.

  Yeah, thank you for pointing it out.
  I'll send revised patch later.

Maybe instead you should change the hpte_need_flush() to always flush
when running on the celleb platform and PREEMPT_RT is enabled.

  Hmm... Is it in linux-2.6.21?  grep'ing it did not help...=20

  Is http://patchwork.ozlabs.org/linuxppc/patch?id=3D10361 is the first pla=
ce
where the hpte_need_flush() appears?

-- owa