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Date: Fri, 22 May 2015 13:43:21 -0400
From: Nikolai Lifanov <lifanov@mail.lifanov.com>
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To: Mateusz Guzik <mjguzik@gmail.com>, Allan Jude <allanjude@freebsd.org>, 
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Subject: Re: xargs -P0 suport
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On 05/22/15 13:27, Mateusz Guzik wrote:
> On Fri, May 22, 2015 at 12:32:52PM -0400, Allan Jude wrote:
>> There is some question about if nargs is a sane value for maxprocs in
>> the negative case. 5000 does seem a bit high, and the behaviour can get
>> wonky depending on the order you specify -P and -n together on the
>> command line.
>>
>> Any suggestions?
>>
> 
> GNU xargs imposes no limit whatsoever, but it also supports reallocating
> its process table, while our xargs allocates one upfront and does not
> change it.
> 
> I would say reading hard proc resource limit and using that as the limit
> would do the job just fine.
> 

GNU xargs uses MAX_INT for this limit. Our xargs performs much worse
with it for a reason I haven't investigated. The 5000 number doesn't
seem high and I have workflows that do '.... | xargs -n1 -P0 ...'
spawning about this many jobs.

- Nikolai Lifanov