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Re: [Qemu-devel] [PATCH] TCG: Improve tb_phys_hash_func()
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From: |
Blue Swirl |
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Subject: |
Re: [Qemu-devel] [PATCH] TCG: Improve tb_phys_hash_func() |
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Date: |
Thu, 30 Dec 2010 17:55:38 +0000 |
On Wed, Dec 29, 2010 at 9:27 PM, Aurelien Jarno <address@hidden> wrote:
> Most of emulated CPU have instructions aligned on 16 or 32 bits, while
> on others GCC tries to align the target jump location. This means that
> 1/2 or 3/4 of tb_phys_hash entries are never used.
>
> Update the hash function tb_phys_hash_func() to ignore the two lowest
> bits of the address. This brings a 6% speed-up when booting a MIPS
> image.
Nice! The beginning of functions may be aligned to 16 bytes. Would it
change the performance figures if one or two more bits were ignored?