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From "William A. Rowe, Jr." <wr...@rowe-clan.net>
Subject Re: Strangely long poll() times
Date Sat, 23 Aug 2003 06:30:53 GMT
At 06:59 PM 8/22/2003, Jim Whitehead wrote:

>>>From what we can tell, the call sequence looks like this:
>
>method_propfind --> ap_xml_parse_input --> ap_get_brigade -->
>core_input_filter --> apr_bucket_read --> socket_bucket_read -->
>apr_socket_recv --> apr_wait_for_io_or_timeout --> apr_poll --> poll
>
>What we found was that just poll() was taking about 31milliseconds, and the
>rest of the functions took only microseconds. Poll acts somewhat like
>select(), and we verified that there was only one file description active at
>the time. Both client and server were on the same local subnet (100Base-T
>wiring), and the PROPFIND request body was relatively small, around
>1500-2500 bytes (we tested for different numbers of properties being
>requested by PROPFIND, hence the variation).
>
>Strangely, when we request 1, 2, 3, ... or 14 properties per request, we see
>this behavior (long poll() response times). But, as soon as we request 15
>properties, things speed up dramatically, to appx. 3-5ms.

Sure sounds like nagling is turned on on the client side.

Bill



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