RE: [f2fs-dev] [PATCH] f2fs: optimize __find_rev_next_bit

From: Chao Yu
Date: Thu Nov 12 2015 - 05:37:23 EST

Hi Fan,

> -----Original Message-----
> From: Fan Li []
> Sent: Thursday, November 12, 2015 8:43 AM
> To: 'Jaegeuk Kim'
> Cc: linux-kernel@xxxxxxxxxxxxxxx; linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx
> Subject: [f2fs-dev] [PATCH] f2fs: optimize __find_rev_next_bit
> 1. Skip __reverse_ulong if the bitmap is empty.
> 2. Reduce branches and codes.
> According to my test, the performance of this new version is 5% higher on
> an empty bitmap of 64bytes, and remains about the same in the worst scenario.

Good catch!

IMO, it's better to optimize __find_rev_next_{,zero}bit together. :)


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