From: Avi Kivity <avi@redhat.com>
To: Andi Kleen <andi@firstfloor.org>, Ingo Molnar <mingo@elte.hu>
Cc: x86@kernel.org, linux-kernel <linux-kernel@vger.kernel.org>,
KVM list <kvm@vger.kernel.org>
Subject: Re: [PATCH 0/3] Remove interrupt stack table usage from x86_64 kernel
Date: Sun, 28 Dec 2008 22:08:35 +0200 [thread overview]
Message-ID: <4957DCC3.3060505@redhat.com> (raw)
In-Reply-To: <4957D14B.60805@redhat.com>
Avi Kivity wrote:
> Avi Kivity wrote:
>> 1. Add per-cpu IDT
>
> Or we could have just two IDTs - one with IST and one without. I
> clocked LIDT at 58 cycles (and we need two per heavyweight switch), so
> it's not that wonderful.
This makes the whole thing unworthwhile. The vmload/vmsave pair costs
only 200 cycles (I should have started with this), and 120 cycles on the
heavyweight path plus complexity are not worth 200 cycles on the
lightweight path.
--
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.
next prev parent reply other threads:[~2008-12-28 20:08 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-12-25 20:58 [PATCH 0/3] Remove interrupt stack table usage from x86_64 kernel Avi Kivity
2008-12-25 20:58 ` [PATCH 1/3] x86: drop the use of the tss interrupt stack table (IST) Avi Kivity
2008-12-25 20:58 ` [PATCH 2/3] x86: Remove pda.irqcount Avi Kivity
2008-12-25 20:58 ` [PATCH 3/3] x86: Switch critical exceptions and NMI to irqstack Avi Kivity
2008-12-26 9:15 ` [PATCH 0/3] Remove interrupt stack table usage from x86_64 kernel Ingo Molnar
[not found] ` <87vdt5vfxc.fsf@basil.nowhere.org>
[not found] ` <4956A0B1.1060908@redhat.com>
[not found] ` <20081227224029.GB496@one.firstfloor.org>
[not found] ` <49573FE7.9090802@redhat.com>
[not found] ` <20081228131605.GC496@one.firstfloor.org>
2008-12-28 14:09 ` Avi Kivity
2008-12-28 19:08 ` Andi Kleen
2008-12-28 19:07 ` Avi Kivity
2008-12-28 19:19 ` Avi Kivity
2008-12-28 20:08 ` Avi Kivity [this message]
2008-12-28 20:34 ` Andi Kleen
2008-12-28 20:28 ` Avi Kivity
2008-12-28 19:30 ` Andi Kleen
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