HPUX 11.0 Slow HTTP File Upload

[Clemens van Everdingen]

Hi,

Found a similar thread with apache performance problem.
In the answer there is a tuning document.
Might be worth looking at.

http://forums.itrc.hp.com/cm/QuestionAnswer/1,,0x0b1206350fe2d61190050090279cd0f9,00.html

C.

[U.SivaKumar_2]

Hi,

From same RFC 18675.2 Deferred file transmission


"The HTTP protocol may require a content-length for the overall
transmission. Even if it were not to do so, HTTP clients are
encouraged to supply content-length for overall file input so that a
busy server could detect if the proposed file data is too large to be
processed reasonably and just return an error code and close the
connection without waiting to process all of the incoming data. Some
current implementations of CGI require a content-length in all POST
transactions.

If the INPUT tag includes the attribute MAXLENGTH, the user agent
should consider its value to represent the maximum Content-Length (in
bytes) which the server will accept for transferred files. In this
way, servers can hint to the client how much space they have
available for a file upload, before that upload takes place. It is
important to note, however, that this is only a hint, and the actual
requirements of the server may change between form creation and file
submission.

In any case, a HTTP server may abort a file upload in the middle of
the transaction if the file being received is too large."

Does your setup meet this.

regards,
U.SivaKumar

[Dhilip Krishnan]

Thanx for all the replies.

I have gone through all the apache tunning docs and implemented all the params upfront.

Packet traces have shown that the client is indeed sending the correct content length to the server while uploading the file.
We used tcpdump to capture the HTTP POST request and could see the content length header correctly.

The fact that the same client i.e. Internet Explorer 5.5 is 5x faster when uploading a file to Apache on LINUX suggestes that the problem is some where on the server side.

We have tried various combinations of clients and servers and finally convinced ourselves that the problem is specific to HPUX networking.

This is the primary reason for me posting this message in the section on HPUX networking!

Pls take a look at the tcpdump output and you will see duplicate acks from both parties.
Client-Windows 2000 (10.1.1.13), HPUX 11.0 server (ccux09.c2.cv.hp.com).
(Below is an observation from one of my peers..)
The client doesn't seem to always ACK received data, which causes totally un-needed retransmits. HPUX doesn't always completely fill the TCP window sent by the client; the combination of these causes some odd behaviour with fragmentation.

Again my question is why is the server ack'ing over and over?