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Date: Fri, 06 Jun 2008 00:25:39 +0200
From: Kris Kennaway <kris@FreeBSD.org>
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Cc: freebsd-questions@freebsd.org
Subject: Re: Poor read() performance, and I can't profile it
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Kirk Strauser wrote:
> On Thursday 05 June 2008, Kris Kennaway wrote:
>> Kirk Strauser wrote:
> 
>> ktrace(1) and check for the buffer size in use.  It is probably too
>> small.
>>
>> Kris
> 
> It seems to be doing a lot of read()s with 4096-byte buffers.  Is that what 
> you mean?  It's also doing a lot of lseek()s to what is likely the current 
> position anyway (example: seek to 0x00, read 16 bytes, seek to 0x10, etc.).  
> Would that make a difference, or should that be a NOP?

No, if it's reading in 16 byte units it will explain the terrible 
performance.

Kris