pipe POLLOUT oddity

[John Gardiner Myers]

This is a cryptographically signed message in MIME format.

--------------ms030009030702030206040504
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit

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.

--------------ms030009030702030206040504
Content-Type: application/x-pkcs7-signature; name="smime.p7s"
Content-Transfer-Encoding: base64
Content-Disposition: attachment; filename="smime.p7s"
Content-Description: S/MIME Cryptographic Signature
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--------------ms030009030702030206040504--