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From: Denis Excoffier <3.1416@free.fr>
To: cygwin@cygwin.com
In-Reply-To: <20110318180247.GA24890@ednor.casa.cgf.cx>
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Subject: Re: last snapshot (2011-03-13)
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Date: Fri, 18 Mar 2011 19:39:39 +0100
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Le 18 mars 2011 =E0 19:02, Christopher Faylor a =E9crit :

>
> Or, are you saying that you still see failures when setting the buffer
> size down to 64K?
With a buffer 64k all is fine.
With a buffer 31*1024*1024, that's different. It seems that
all pipes open at the same time add their buffers up to an upper limit=20=
=20
(the nonpaged value)
which cannot be exceeded.

This also explains a failure i had this afternoon, on the CPU which=20=20
was normally "non-failing":
i launched 5 xz-compressions at the same time (not big ones, but you=20=20
must know that xz-compression
can be rather slow even on small files, so it is very likely that the=20=20
5 were concurrent); and 3
of them failed unexpectedly. I understand now that 5 open pipes at the=20=
=20
same time would use
5*31*1024*1024 bytes, which is too much for a CPU that has=20=20
nonpaged=3D98Mb as i said in my previous
message.

Now, i suppose that with a 64k buffer, you would not be able to exceed=20=
=20
98Mb/64kb=3D1568 open pipes at the
same time.

Denis Excoffier.


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