From: Andi Kleen <ak@suse.de>
To: Ingo Molnar <mingo@elte.hu>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>,
Keir Fraser <Keir.Fraser@cl.cam.ac.uk>,
"H. Peter Anvin" <hpa@zytor.com>,
LKML <linux-kernel@vger.kernel.org>,
Jan Beulich <jbeulich@novell.com>,
Eduardo Pereira Habkost <ehabkost@redhat.com>,
Ian Campbell <ijc@hellion.org.uk>,
William Irwin <wli@holomorphy.com>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH 11 of 11] x86: defer cr3 reload when doing pud_clear()
Date: Sat, 26 Jan 2008 06:57:03 +0100 [thread overview]
Message-ID: <200801260657.04398.ak@suse.de> (raw)
In-Reply-To: <20080126001128.GB24559@elte.hu>
On Saturday 26 January 2008 01:11:28 Ingo Molnar wrote:
(plus
> any add-on TLB miss costs - but those are amortized quite well as long
> as the pagetables are well cached - which they usually are on today's
> 2MB-ish L2 caches),
Did you measure the cost of that amortizing too?
My guess is that especially with TLBs getting larger and larger the
cost of full CR3 flushes are rising.
> so INVLPG makes sense for pagetable fault realated single-address
> flushes, but they rarely make sense for range flushes. (and that's how
> Linux uses it)
I think it would be an interesting experiment to switch flush_tlb_range()
over to INVLPG if the length is below some threshold and see if there
are visible effects in macro benchmarks. The main problem
would be to determine the right threshold -- would likely be CPU dependent.
-Andi
next prev parent reply other threads:[~2008-01-26 5:57 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-01-25 21:23 [PATCH 00 of 11] x86: separate pmd lifetime from pgd Jeremy Fitzhardinge
2008-01-25 21:23 ` [PATCH 01 of 11] xen: fix mismerge in masking pte flags Jeremy Fitzhardinge
2008-01-25 21:23 ` [PATCH 02 of 11] x86: use the same pgd_list for PAE and 64-bit Jeremy Fitzhardinge
2008-01-25 21:23 ` [PATCH 03 of 11] x86: add mm parameter to paravirt_alloc_pd Jeremy Fitzhardinge
2008-01-25 21:23 ` [PATCH 04 of 11] x86: fix early_ioremap pagetable ops Jeremy Fitzhardinge
2008-01-31 19:01 ` Ian Campbell
2008-01-31 19:52 ` Jeremy Fitzhardinge
2008-01-31 20:37 ` Ingo Molnar
2008-01-31 20:41 ` Jeremy Fitzhardinge
2008-01-25 21:23 ` [PATCH 05 of 11] x86: demacro asm-x86/pgalloc_32.h Jeremy Fitzhardinge
2008-01-25 21:23 ` [PATCH 06 of 11] x86: unify PAE/non-PAE pgd_ctor Jeremy Fitzhardinge
2008-01-25 21:23 ` [PATCH 07 of 11] x86: don't special-case pmd allocations as much Jeremy Fitzhardinge
2008-01-25 21:23 ` [PATCH 08 of 11] xen: deal with pmd being allocated/freed Jeremy Fitzhardinge
2008-01-25 21:23 ` [PATCH 09 of 11] x86: preallocate pmds at pgd creation time Jeremy Fitzhardinge
2008-01-25 21:23 ` [PATCH 10 of 11] x86: allocate and initialize unshared pmds Jeremy Fitzhardinge
2008-01-25 21:23 ` [PATCH 11 of 11] x86: defer cr3 reload when doing pud_clear() Jeremy Fitzhardinge
2008-01-25 21:37 ` H. Peter Anvin
2008-01-25 22:54 ` Jeremy Fitzhardinge
2008-01-25 23:38 ` Keir Fraser
2008-01-25 23:44 ` Jeremy Fitzhardinge
2008-01-26 0:11 ` Ingo Molnar
2008-01-26 0:20 ` H. Peter Anvin
2008-01-26 5:57 ` Andi Kleen [this message]
2008-01-26 6:03 ` H. Peter Anvin
2008-01-26 0:10 ` H. Peter Anvin
2008-01-26 0:57 ` Jeremy Fitzhardinge
2008-01-26 1:09 ` H. Peter Anvin
2008-01-28 15:17 ` [PATCH 00 of 11] x86: separate pmd lifetime from pgd Ingo Molnar
2008-01-28 15:39 ` Jeremy Fitzhardinge
2008-01-28 15:41 ` Ingo Molnar
2008-01-28 15:47 ` Ingo Molnar
2008-01-28 16:20 ` Jeremy Fitzhardinge
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