[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH 1/9] TCG "sync" op
From: |
Ulrich Hecht |
Subject: |
Re: [Qemu-devel] [PATCH 1/9] TCG "sync" op |
Date: |
Mon, 19 Oct 2009 19:17:55 +0200 |
User-agent: |
KMail/1.9.10 |
On Saturday 17 October 2009, Edgar E. Iglesias wrote:
> I looked at the s390 patches and was also unsure about this sync op.
> I'm not convinced it's bad but my first feeling was as Aurelien points
> out that the translator shoud take care of it.
Indeed. I would have expected it to, in fact. But it doesn't. The sync op
is the simplest and quickest way to get what I want that I could come up
with. I'd be perfectly happy if TCG could handle aliases on its own, but
doing a lot of ALU operations on every register access is not an option.
> Another thing I noticed was the large amount of helpers. Without
> looking at the details my feeling was that you could probably do more
> at translation time.
My experience is that helper functions have an undeservedly bad image. A
pure const helper call is very easy to optimize away for TCG. Random bit
shifting, comparing and branching isn't.
> Nice work!
Thank you.
CU
Uli
--
SUSE LINUX Products GmbH, GF: Markus Rex, HRB 16746 (AG Nürnberg)
- [Qemu-devel] [PATCH 9/9] linux-user: getpriority errno fix, (continued)
- [Qemu-devel] [PATCH 9/9] linux-user: getpriority errno fix, Ulrich Hecht, 2009/10/16
- Re: [Qemu-devel] [PATCH 3/9] S/390 host/target build system support, Aurelien Jarno, 2009/10/17
- Re: [Qemu-devel] [PATCH 2/9] S/390 CPU emulation, Aurelien Jarno, 2009/10/17
- Re: [Qemu-devel] [PATCH 2/9] S/390 CPU emulation, Ulrich Hecht, 2009/10/19
- Re: [Qemu-devel] [PATCH 2/9] S/390 CPU emulation, Aurelien Jarno, 2009/10/22
Re: [Qemu-devel] [PATCH 1/9] TCG "sync" op, Aurelien Jarno, 2009/10/16
Re: [Qemu-devel] [PATCH 1/9] TCG "sync" op, Edgar E. Iglesias, 2009/10/17
Re: [Qemu-devel] [PATCH 1/9] TCG "sync" op,
Ulrich Hecht <=