pipe POLLOUT oddity

John Gardiner Myers (jgmyers@netscape.com)
Tue, 05 Nov 2002 10:15:33 -0800


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Mark Mielke wrote:

>On Fri, Nov 01, 2002 at 03:27:41PM -0800, John Gardiner Myers wrote:
>
>
>>There's also the oddity that I noticed this week: pipes don't report
>>POLLOUT readiness through the classic poll interface until the pipe's
>>buffer is completely empty. Changing this to report POLLOUT readiness
>>when the pipe's buffer is not full apparently causes NIS to break.
>>
>>
>
>These seems deficient. Does this mean that pipes managed via poll() are
>not able to maximum throughput?
>
I could see this going either way, depending on the application.
Holding off the POLLOUT readiness could improve performance by making
sure that whenever a process is scheduled to write to a pipe the pipe
has enough buffer to take all of the data.

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