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Re: Test failures in blead on ppc64

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From:
ilmari
Date:
October 7, 2014 15:08
Subject:
Re: Test failures in blead on ppc64
Message ID:
d8jbnpn2a0h.fsf@dalvik.ping.uio.no
Dave Mitchell <davem@iabyn.com> writes:

> On Mon, Oct 06, 2014 at 09:38:11PM +0200, Ævar Arnfjörð Bjarmason wrote:
> Ah, sorry; I completely failed to spot the obvious in your OP.
>
>> -$buf = "a" x 1_000_000 . "\n"; # bigger than any pipe buffer hopefully
>> +$buf = "a" x 1_000_000_000 . "\n"; # bigger than any pipe buffer hopefully
>
> Interesting. Are you able to find a smaller value that still blocks?
> I should imagine a 1Gb string might choke small systems.

The (Linux-specific) F_GETPIPE_SZ fcntl returns the size of the pipe
buffer, and the fs.pipe-max-size sysctl (or the
/proc/sys/fs/pipe-max-size file) has the max size an unprivileged
process can set it to.  They are 64KiB and 1MiB respectively on this
x86_64 Linux 3.2 box (Ubuntu 12.04).

-- 
"A disappointingly low fraction of the human race is,
 at any given time, on fire." - Stig Sandbeck Mathisen


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