From: Jeremy Fitzhardinge <jeremy@goop.org>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Zachary Amsden <zach@vmware.com>, Nick Piggin <npiggin@suse.de>,
Ingo Molnar <mingo@elte.hu>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
"jeremy@xensource.com" <jeremy@xensource.com>,
"chrisw@sous-sol.org" <chrisw@sous-sol.org>,
"rusty@rustcorp.com.au" <rusty@rustcorp.com.au>,
Andrew Morton <akpm@linux-foundation.org>,
Xen-devel <xen-devel@lists.xensource.com>
Subject: Re: lmbench lat_mmap slowdown with CONFIG_PARAVIRT
Date: Thu, 22 Jan 2009 16:08:15 -0800 [thread overview]
Message-ID: <49790A6F.1080000@goop.org> (raw)
In-Reply-To: <497906A4.2030008@zytor.com>
H. Peter Anvin wrote:
> Right now a number of the call sites contain a huge push/pop sequence
> followed by an indirect call. We can patch in the native code to
> avoid the branch overhead, but the register constraints and icache
> footprint is unchanged.
That's true for the pvops hooks emitted in the .S files, but not so true
for ones in C code (well, there are no explicit push/pops, but the
presence of the call may cause the compiler to generate them).
The .S hooks can definitely be cleaned up, but I don't think that's
germane to Nick's observations that the mm code is showing slowdowns.
J
next prev parent reply other threads:[~2009-01-23 0:08 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-01-20 11:05 lmbench lat_mmap slowdown with CONFIG_PARAVIRT Nick Piggin
2009-01-20 11:26 ` Ingo Molnar
2009-01-20 12:34 ` Nick Piggin
2009-01-20 12:45 ` Ingo Molnar
2009-01-20 13:41 ` Nick Piggin
2009-01-20 14:03 ` Ingo Molnar
2009-01-20 14:14 ` Nick Piggin
2009-01-20 14:17 ` Ingo Molnar
2009-01-20 14:41 ` Nick Piggin
2009-01-20 15:00 ` Ingo Molnar
2009-01-20 15:13 ` Ingo Molnar
2009-01-20 19:37 ` Ingo Molnar
2009-01-20 20:45 ` Jeremy Fitzhardinge
2009-01-20 20:56 ` Ingo Molnar
2009-01-21 7:27 ` Nick Piggin
2009-01-21 22:23 ` Jeremy Fitzhardinge
2009-01-22 22:28 ` Zachary Amsden
2009-01-22 22:44 ` Jeremy Fitzhardinge
2009-01-22 22:49 ` H. Peter Anvin
2009-01-22 22:58 ` Zachary Amsden
2009-01-22 23:52 ` H. Peter Anvin
2009-01-23 0:08 ` Jeremy Fitzhardinge [this message]
2009-01-22 22:55 ` Zachary Amsden
2009-01-23 0:14 ` Jeremy Fitzhardinge
2009-01-27 7:59 ` Ingo Molnar
2009-01-27 8:24 ` Jeremy Fitzhardinge
2009-01-27 10:17 ` Jeremy Fitzhardinge
2009-01-20 19:05 ` Zachary Amsden
2009-01-20 19:31 ` Ingo Molnar
2009-01-22 22:26 ` Jeremy Fitzhardinge
2009-01-22 23:04 ` Ingo Molnar
2009-01-22 23:30 ` Zachary Amsden
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