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Date:      Fri, 5 Apr 1996 14:13:11 -0500 (EST)
From:      Marc Ramirez <mrami@mramirez.sy.yale.edu>
To:        Satoshi Asami <asami@cs.berkeley.edu>
Cc:        current@freebsd.org, nisha@cs.berkeley.edu, tege@matematik.su.se, hasty@rah.star-gate.com
Subject:   Re: fast memory copy for large data sizes
Message-ID:  <Pine.BSF.3.91.960405141056.2754A-100000@mramirez.sy.yale.edu>
In-Reply-To: <199604050935.BAA24263@silvia.HIP.Berkeley.EDU>

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On Fri, 5 Apr 1996, Satoshi Asami wrote:

> We've put together a fast memory copy that uses floating point
> registers to speed up large transfers.  The original idea was taken
> from Amancio Hasty's old post to use floating point registers to move
> 8 bytes at a time.  (We tried using integer registers too but with our
> wits we could only get 10MB/s less than the FP case.)

P5's and up only, please. :)  AMD 486/66:

mrami[~/bcopy]$ make
>> running tests
sh runtests
    size     libc             ours
      32   7.629395 MB/s   7.629395 MB/s
      64  12.207031 MB/s   4.695012 MB/s
     128  12.207031 MB/s   3.487723 MB/s
     256  12.207031 MB/s   6.424753 MB/s
     512  12.520032 MB/s   7.076540 MB/s
    1024  12.682630 MB/s   7.454676 MB/s
    2048  12.682630 MB/s   7.570252 MB/s
    4096  10.146104 MB/s   7.629395 MB/s
    8192  12.682630 MB/s   7.666830 MB/s
   16384  12.703252 MB/s   7.689469 MB/s
   32768  12.682630 MB/s   7.517440 MB/s
   65536  12.183236 MB/s   7.472501 MB/s
  131072  12.090144 MB/s   7.526040 MB/s
  262144  12.569762 MB/s   7.717717 MB/s
  524288  12.419583 MB/s   7.534773 MB/s
 1048576  11.838803 MB/s   7.718551 MB/s
 2097152  12.164192 MB/s   7.725020 MB/s
 4194304  12.290410 MB/s   7.719504 MB/s
mrami[~/bcopy]$

Marc.

--
Every four seconds a woman has a baby.  Our problem is to find this
woman and stop her.




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