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Re: [Qemu-devel] [PULL for-2.5 2/4] block: Don't wait serialising for no
From: |
Peter Maydell |
Subject: |
Re: [Qemu-devel] [PULL for-2.5 2/4] block: Don't wait serialising for non-COR read requests |
Date: |
Tue, 8 Dec 2015 14:15:22 +0000 |
On 8 December 2015 at 13:45, Kevin Wolf <address@hidden> wrote:
> Coroutines don't save the FPU state, so you're not supposed to use
> floating point operations inside coroutines. That the compiler spills
> some integer value into a floating point register is a bit nasty...
The compiler will happily use FP registers even for apparently
integer code if it thinks that is a better way to do it (eg on
some CPUs doing memcpy and other kinds of block data move may
go faster via the FPU registers, or it might be faster to spill
an integer register into an FP register rather than spilling it
to memory). As I see you've already determined, it's the
job of setjmp/longjmp to make sure that everything is saved
and restored correctly, fp or otherwise...
thanks
-- PMM
- Re: [Qemu-devel] [PULL for-2.5 2/4] block: Don't wait serialising for non-COR read requests, (continued)
- Re: [Qemu-devel] [PULL for-2.5 2/4] block: Don't wait serialising for non-COR read requests, Kevin Wolf, 2015/12/08
- Re: [Qemu-devel] [PULL for-2.5 2/4] block: Don't wait serialising for non-COR read requests, Cornelia Huck, 2015/12/08
- Re: [Qemu-devel] [PULL for-2.5 2/4] block: Don't wait serialising for non-COR read requests, Christian Borntraeger, 2015/12/08
- Re: [Qemu-devel] [PULL for-2.5 2/4] block: Don't wait serialising for non-COR read requests, Christian Borntraeger, 2015/12/08
- Re: [Qemu-devel] [PULL for-2.5 2/4] block: Don't wait serialising for non-COR read requests, Kevin Wolf, 2015/12/08
- Re: [Qemu-devel] [PULL for-2.5 2/4] block: Don't wait serialising for non-COR read requests, Christian Borntraeger, 2015/12/08
- Re: [Qemu-devel] [PULL for-2.5 2/4] block: Don't wait serialising for non-COR read requests, Christian Borntraeger, 2015/12/08
- Re: [Qemu-devel] [PULL for-2.5 2/4] block: Don't wait serialising for non-COR read requests, Kevin Wolf, 2015/12/08
- Re: [Qemu-devel] [PULL for-2.5 2/4] block: Don't wait serialising for non-COR read requests, Christian Borntraeger, 2015/12/08
- Re: [Qemu-devel] [PULL for-2.5 2/4] block: Don't wait serialising for non-COR read requests, Cornelia Huck, 2015/12/08
- Re: [Qemu-devel] [PULL for-2.5 2/4] block: Don't wait serialising for non-COR read requests,
Peter Maydell <=
[Qemu-devel] [PULL for-2.5 3/4] iotests: Add "add_drive_raw" method, Stefan Hajnoczi, 2015/12/03
[Qemu-devel] [PULL for-2.5 4/4] iotests: Add regresion test case for write notifier assertion failure, Stefan Hajnoczi, 2015/12/03
Re: [Qemu-devel] [PULL for-2.5 0/4] Block patches, Peter Maydell, 2015/12/03