Re: [PATCH] md5: accepts a new --threads option

[Jim Meyering]

Pádraig Brady wrote:

> Pádraig Brady wrote:
>> Giuseppe Scrivano wrote:
>>> Hello,
>>>
>>> inspired by the attempt to make `sort' multi-threaded, I added threads
>>> support to md5sum and the sha* programs family.  It has effect only when
>>> multiple files are specified.
>>>
>>> Any comment?
>>
>> How does it compare to:
>>
>> files_per_process=10
>> cpus=4
>> find files | xargs -n$files_per_process -P$cpus md5sum
>>
>> I would expect it to be a bit better as file_per_process
>> could be very large, thus having less overhead in starting
>> processes. Though is the benefit worth the extra implementation
>> complexity and new less general interface for users?
>
> Hi James,
>
> I was wondering would it be worth adding the nproc module to xargs
> to support -P without any options to use the number of CPUs
> as the value.
>
> Hmm, I could see it being useful to specify NCPUs-1 also.
> I wonder is there a general external method to determine
> the number of CPUs.

As far as I know, there is nothing portable.
Want to add another program to coreutils?
With what Bruno has just added to gnulib's nproc module,
we should have most platforms covered.