From: Paolo Bonzini <pbonzini@redhat.com>
To: "Emilio G. Cota" <cota@braap.org>
Cc: qemu-devel@nongnu.org,
Peter Crosthwaite <crosthwaite.peter@gmail.com>,
Richard Henderson <rth@twiddle.net>,
Peter Maydell <peter.maydell@linaro.org>,
Eduardo Habkost <ehabkost@redhat.com>,
Claudio Fontana <claudio.fontana@huawei.com>,
Andrzej Zaborowski <balrogg@gmail.com>,
Aurelien Jarno <aurelien@aurel32.net>,
Alexander Graf <agraf@suse.de>, Stefan Weil <sw@weilnetz.de>,
qemu-arm@nongnu.org, alex.bennee@linaro.org,
Pranith Kumar <bobby.prani+qemu@gmail.com>
Subject: Re: [Qemu-devel] [PATCH 09/10] target/i386: optimize indirect branches with TCG's jr op
Date: Fri, 14 Apr 2017 13:17:47 +0800 [thread overview]
Message-ID: <df0a4da6-4f3e-3b44-ebbc-988017e29246@redhat.com> (raw)
In-Reply-To: <20170413014646.GA1474@flamenco>
> Any other instructions I should look into? Perhaps lret/lret im?
Possibly (for completeness), but they are extremely rare in 32- and
64-bit code.
You also didn't cover any of syscall/sysret and sysenter/sysexit in your
patch, which would be on a relatively slow path but not _that_ slow.
But that probably should be a separate patch, moving the env->eip
assignment from seg_helper.c to translate.c and using the resulting TCGv
as the argument for jr.
Paolo
> Anyway, nbench does not improve much with the above. The reason seems to be
> that it's full of direct jumps (visible with -d in_asm). Also tried softmmu
> to see whether these jumps are in-page or not: peak improvement is ~8%, so
> I guess most of them are in-page. See http://imgur.com/EKRrYUz
>
> I'm running new tests on a server with no other users and which has
> frequency scaling disabled. This should help get less noisy numbers,
> since I'm having trouble replicating my own results :> (I used my desktop
> machine until now). Will post these numbers tomorrow (running overnight
> SPECint both train and set sizes).
>
> Thanks,
>
> Emilio
>
next prev parent reply other threads:[~2017-04-14 5:18 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-12 1:17 [Qemu-devel] [PATCH 00/10] TCG optimizations for 2.10 Emilio G. Cota
2017-04-12 1:17 ` [Qemu-devel] [PATCH 01/10] exec-all: add tb_from_jmp_cache Emilio G. Cota
2017-04-12 1:17 ` [Qemu-devel] [PATCH 02/10] exec-all: inline tb_from_jmp_cache Emilio G. Cota
2017-04-12 1:17 ` [Qemu-devel] [PATCH 03/10] target/arm: optimize cross-page block chaining in softmmu Emilio G. Cota
2017-04-15 11:24 ` Richard Henderson
2017-04-12 1:17 ` [Qemu-devel] [PATCH 04/10] target/i386: " Emilio G. Cota
2017-04-12 1:17 ` [Qemu-devel] [PATCH 05/10] tcg: add jr opcode Emilio G. Cota
2017-04-13 5:09 ` Paolo Bonzini
2017-04-15 11:40 ` Richard Henderson
2017-04-16 18:28 ` Emilio G. Cota
2017-04-12 1:17 ` [Qemu-devel] [PATCH 06/10] tcg: add brcondi_ptr Emilio G. Cota
2017-04-12 1:17 ` [Qemu-devel] [PATCH 07/10] tcg: add tcg_temp_local_new_ptr Emilio G. Cota
2017-04-12 1:17 ` [Qemu-devel] [PATCH 08/10] target/arm: optimize indirect branches with TCG's jr op Emilio G. Cota
2017-04-12 1:17 ` [Qemu-devel] [PATCH 09/10] target/i386: " Emilio G. Cota
2017-04-12 3:43 ` Paolo Bonzini
2017-04-13 1:46 ` Emilio G. Cota
2017-04-14 5:17 ` Paolo Bonzini [this message]
2017-04-12 1:17 ` [Qemu-devel] [PATCH 10/10] tb-hash: improve tb_jmp_cache hash function in user mode Emilio G. Cota
2017-04-12 3:46 ` Paolo Bonzini
2017-04-12 5:07 ` Emilio G. Cota
2017-04-12 10:03 ` [Qemu-devel] [PATCH 00/10] TCG optimizations for 2.10 Alex Bennée
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