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Re: [Qemu-devel] [PATCH] translate: optimize gen_intermediate_code_inter
From: |
li guang |
Subject: |
Re: [Qemu-devel] [PATCH] translate: optimize gen_intermediate_code_internal |
Date: |
Thu, 11 Apr 2013 10:12:07 +0800 |
在 2013-04-09二的 17:20 +0800,陳韋任 (Wei-Ren Chen)写道:
> Hi liguang,
>
> On Tue, Apr 09, 2013 at 04:21:10PM +0800, li guang wrote:
> > 在 2013-04-09二的 10:11 +0200,Paolo Bonzini写道:
> > > Il 09/04/2013 10:05, 陳韋任 (Wei-Ren Chen) ha scritto:
> > > > Hi liguang,
> > > >
> > > > Just to be curious, how much performance improvement this patch can
> > > > get?
> > >
> > > I think zero. It is indeed making the code a tiny bit more readable in
> > > the 2nd/3rd/5th/6th hunks.
> >
> > I think maybe a little greater than 0,
> > for it optimizes a variable 'lj' increment.
>
> As Peter said, only profiling can show if there is a performance
> improvement.
>
> > > But the 1st and 4th hunks, which do
> > >
> > > - num_insns = 0;
> > >
> > > are wrong. I'm surprised the compiler doesn't report usage of an
> > > uninitialized variable. liguang, how did you test them?
> >
> > I do normal compile and run guest OS for TCG,
> > I think 'max_insns = tb->cflags & CF_COUNT_MASK;' is enough
> > to feed compiler.
>
> num_insns and max_insns are two different variables, right? So this
> assignment does not do anything with num_insns.
Yes, you're right.
Thanks!
>
> Regards,
> chenwj
>
- Re: [Qemu-devel] [PATCH] translate: optimize gen_intermediate_code_internal, (continued)
- Re: [Qemu-devel] [PATCH] translate: optimize gen_intermediate_code_internal, Paolo Bonzini, 2013/04/09
- Re: [Qemu-devel] [PATCH] translate: optimize gen_intermediate_code_internal, Wei-Ren Chen, 2013/04/09
- Re: [Qemu-devel] [PATCH] translate: optimize gen_intermediate_code_internal, li guang, 2013/04/09
- Re: [Qemu-devel] [PATCH] translate: optimize gen_intermediate_code_internal, Peter Maydell, 2013/04/09
- Re: [Qemu-devel] [PATCH] translate: optimize gen_intermediate_code_internal, li guang, 2013/04/09
- Re: [Qemu-devel] [PATCH] translate: optimize gen_intermediate_code_internal, Wei-Ren Chen, 2013/04/09
- Re: [Qemu-devel] [PATCH] translate: optimize gen_intermediate_code_internal, li guang, 2013/04/09
- Re: [Qemu-devel] [PATCH] translate: optimize gen_intermediate_code_internal, Wei-Ren Chen, 2013/04/09
- Re: [Qemu-devel] [PATCH] translate: optimize gen_intermediate_code_internal, li guang, 2013/04/09
- Re: [Qemu-devel] [PATCH] translate: optimize gen_intermediate_code_internal, Wei-Ren Chen, 2013/04/09
- Re: [Qemu-devel] [PATCH] translate: optimize gen_intermediate_code_internal,
li guang <=