From: Suresh Siddha <suresh.b.siddha@intel.com>
To: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
"H. Peter Anvin" <hpa@zytor.com>, Len Brown <lenb@kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [patch] x86, tlb: switch cr3 in leave_mm() only when needed
Date: Mon, 26 Mar 2012 15:47:05 -0700 [thread overview]
Message-ID: <1332802025.12381.2.camel@sbsiddha-desk.sc.intel.com> (raw)
In-Reply-To: <20120323083751.GC2886@gmail.com>
On Fri, 2012-03-23 at 09:37 +0100, Ingo Molnar wrote:
> * Suresh Siddha <suresh.b.siddha@intel.com> wrote:
>
> > I was reviewing this code in some other context and thought
> > this optimization makes sense. Unless someone beats me, I can
> > collect some data on Monday.
>
> Would be really nice to get this data.
>
On an idle system with 32logical cpu's (2 socket/8-core each) the
original kernel did the unnecessary load_cr3 2988 times during an
interval of 5 seconds.
With the fix, that count drops to 9 times.
thanks,
suresh
next prev parent reply other threads:[~2012-03-26 22:45 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-22 23:33 Suresh Siddha
2012-03-22 23:44 ` Linus Torvalds
2012-03-23 0:01 ` Suresh Siddha
2012-03-23 0:20 ` H. Peter Anvin
2012-03-23 0:37 ` Linus Torvalds
2012-03-23 0:51 ` Suresh Siddha
2012-03-23 8:37 ` Ingo Molnar
2012-03-26 22:47 ` Suresh Siddha [this message]
2012-03-26 22:47 ` H. Peter Anvin
2012-03-23 0:31 ` [tip:x86/mm] x86, tlb: Switch " tip-bot for Suresh Siddha
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