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Re: [Qemu-devel] [PATCH 09/10] target-alpha: Implement load-locked/store
From: |
Jamie Lokier |
Subject: |
Re: [Qemu-devel] [PATCH 09/10] target-alpha: Implement load-locked/store-conditional properly. |
Date: |
Fri, 26 Mar 2010 01:55:45 +0000 |
User-agent: |
Mutt/1.5.13 (2006-08-11) |
Richard Henderson wrote:
> On 03/25/2010 10:40 AM, Blue Swirl wrote:
> > Sparc V8 has two atomic instructions, ldstub and swap.
>
> I know -- but not the CAS operation being discussed here.
>
> As I think about this more and more, the Real Problem is
> not with the CAS, but with the memory ordering requirements
> of the guest vs the memory ordering of the host. It's easy
> to implement things on x86, because of the host's strict
> memory ordering. It would be much more difficult to properly
> emulate x86 on a relaxed memory ordering host. We'd need to
> insert barriers between pairs of qemu_{ld,st} operations.
>
> I may give this some proper thinking this weekend.
Some host architectures have a strongly ordered mode, which might
help, and be faster than putting barriers everywhere.
-- Jamie
- [Qemu-devel] [PATCH 10/10] target-alpha: Enable NPTL., (continued)
- [Qemu-devel] [PATCH 10/10] target-alpha: Enable NPTL., Richard Henderson, 2010/03/24
- [Qemu-devel] [PATCH 09/10] target-alpha: Implement load-locked/store-conditional properly., Richard Henderson, 2010/03/24
- Re: [Qemu-devel] [PATCH 09/10] target-alpha: Implement load-locked/store-conditional properly., Nathan Froyd, 2010/03/25
- Re: [Qemu-devel] [PATCH 09/10] target-alpha: Implement load-locked/store-conditional properly., Richard Henderson, 2010/03/25
- Re: [Qemu-devel] [PATCH 09/10] target-alpha: Implement load-locked/store-conditional properly., Nathan Froyd, 2010/03/25
- Re: [Qemu-devel] [PATCH 09/10] target-alpha: Implement load-locked/store-conditional properly., Richard Henderson, 2010/03/25
- Re: [Qemu-devel] [PATCH 09/10] target-alpha: Implement load-locked/store-conditional properly., Nathan Froyd, 2010/03/25
- Re: [Qemu-devel] [PATCH 09/10] target-alpha: Implement load-locked/store-conditional properly., Richard Henderson, 2010/03/25
- Re: [Qemu-devel] [PATCH 09/10] target-alpha: Implement load-locked/store-conditional properly., Blue Swirl, 2010/03/25
- Re: [Qemu-devel] [PATCH 09/10] target-alpha: Implement load-locked/store-conditional properly., Richard Henderson, 2010/03/25
- Re: [Qemu-devel] [PATCH 09/10] target-alpha: Implement load-locked/store-conditional properly.,
Jamie Lokier <=
- Re: [Qemu-devel] [PATCH 09/10] target-alpha: Implement load-locked/store-conditional properly., Jamie Lokier, 2010/03/25
[Qemu-devel] [PATCH 08/10] target-alpha: Emit goto_tb opcodes., Richard Henderson, 2010/03/24
Re: [Qemu-devel] [PATCH 00/10, v3] target-alpha improvements, Jamie Lokier, 2010/03/25