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Date: Sat, 27 Jul 2013 19:24:35 +0400
From: Solar Designer <>
Subject: Re: md5 hash comparisons

myrice, Sayantan -

On Fri, Jul 26, 2013 at 10:00:21PM -0700, Myrice Li wrote:
> I have bitmaps in both local memory and global memory. It works as follows:
> 1. if loaded hashes number exceeds a threshold, it will use larger mask
> 0xFFFFFF  for hash table lookup and global bitmaps
> 2. otherwise, it will use  0xFFFF for hash table lookup and local memory
> bitmaps.

OK.  Yet 0xFFFFFF won't be large enough with many millions of hashes

> I think I use 2K*4 bitmaps in local memory

IIRC, it was 8 KiB * 4.

> for hash number smaller than
> 6553. For each portion of bitmaps, it actually has 2K(int)*4*8 = 64K bit.

Oh, you meant 2K ints, not 2 KiB.  Then we're in agreement.

> That is what I think Sayantan claims that "64K loaded hash seems fit into
> local memory". But this is not true, For loaded hashes exceeds 6553(1/10 of
> 64K), it will use global memory bitmaps.

Sayantan was not referring to your code at all.



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