[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PULL 5/7] tcg: Add mmu helpers that take a return addr
From: |
Aurelien Jarno |
Subject: |
Re: [Qemu-devel] [PULL 5/7] tcg: Add mmu helpers that take a return address argument |
Date: |
Tue, 27 Aug 2013 17:43:32 +0200 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Tue, Aug 27, 2013 at 07:53:56AM -0700, Richard Henderson wrote:
> On 08/27/2013 03:46 AM, Aurelien Jarno wrote:
> > On the other hand calling the helper is the exception more than the
> > rule (that's why they have been moved at the end of the TB), so we
> > should not look to much at generating fast code, but rather small code
> > in order to use the caches (both TB and CPU caches) more efficiently.
> >
> > Therefore even on x86, if we move the -1 at the helper level, it should
> > be possible to use a tail call for the stores, something like:
> >
> > mov %r14,%rdi
> > mov %ebx,%edx
> > xor %ecx,%ecx
> > lea -0x10f(%rip),%r8 # 0x7f2541a6f69a
> > pushq %r8
> > jmpq 0x7f25526757a0
> >
> > Instead of:
> >
> > mov %r14,%rdi
> > mov %ebx,%edx
> > xor %ecx,%ecx
> > lea -0x10f(%rip),%r8 # 0x7f2541a6f69a
> > callq 0x7f25526757a0
> > jmpq 0x7f2541a6f69b
>
> Fair enough. I'll have a go at some follow-ups then.
>
I think this can also be done in a second time. Do you want to create a
version 3, or should I just process the current pull request and you
will provide additional patches later?
--
Aurelien Jarno GPG: 1024D/F1BCDB73
address@hidden http://www.aurel32.net
- [Qemu-devel] [PULL 0/7] Improve tcg ldst optimization, Richard Henderson, 2013/08/26
- [Qemu-devel] [PULL 1/7] tcg: Tidy generated code for tcg_outN, Richard Henderson, 2013/08/26
- [Qemu-devel] [PULL 2/7] tcg-i386: Add and use tcg_out64, Richard Henderson, 2013/08/26
- [Qemu-devel] [PULL 3/7] tcg-i386: Try pc-relative lea for constant formation, Richard Henderson, 2013/08/26
- [Qemu-devel] [PULL 4/7] tcg-i386: Tidy qemu_ld/st slow path, Richard Henderson, 2013/08/26
- [Qemu-devel] [PULL 5/7] tcg: Add mmu helpers that take a return address argument, Richard Henderson, 2013/08/26
Re: [Qemu-devel] [PULL 5/7] tcg: Add mmu helpers that take a return address argument, Peter Maydell, 2013/08/26
[Qemu-devel] [PULL 6/7] tcg: Tidy softmmu_template.h, Richard Henderson, 2013/08/26
[Qemu-devel] [PULL 7/7] tcg-i386: Use new return-argument ld/st helpers, Richard Henderson, 2013/08/26