Re: [PATCH 5.1] zread: read files in 4k chunks

From	Chet Ramey <chet.ramey@case.edu>
Newsgroups	gnu.bash.bug
Subject	Re: [PATCH 5.1] zread: read files in 4k chunks
Date	2020-06-22 17:07 -0400
Organization	ITS, Case Western Reserve University
Message-ID	<mailman.295.1592860057.2574.bug-bash@gnu.org> (permalink)
References	<20200622055328.155106-1-Jason@zx2c4.com> <3cac1f66-697d-396d-3dc8-fc5b621638a4@case.edu> <271ebec9-fe1f-7823-a236-2e734657a279@iki.fi> <9994508a-78f5-cac9-053c-df504f459c73@case.edu>

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On 6/22/20 4:16 PM, Ilkka Virta wrote:
> On 22.6. 19.35, Chet Ramey wrote:
>> On 6/22/20 1:53 AM, Jason A. Donenfeld wrote:
>>> Currently a static sized buffer is used for reading files. At the moment
>>> it is extremely small, making parsing of large files extremely slow.
>>> Increase this to 4k for improved performance.
>>
>> I bumped it up to 1024 initially for testing.
> 
> It always struck me as odd that Bash used such a small read of 128 bytes.
> Most of the GNU utils I've looked at on Debian use 8192, and a simple test
> program seems to indicate glibc's stdio reads 4096 bytes at one read() call.

Yes, 128 is too small for modern systems. It made more sense when the code
was written.


-- 
``The lyf so short, the craft so long to lerne.'' - Chaucer
		 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU    chet@case.edu    http://tiswww.cwru.edu/~chet/

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Re: [PATCH 5.1] zread: read files in 4k chunks Chet Ramey <chet.ramey@case.edu> - 2020-06-22 17:07 -0400

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