Bill, As we suspected based on this information, setting the TF_NODELAY flag in the accept callback did not make a difference. Apparently the problem is somewhere else in the stack but not sure where. I tried both MSIE and FoxFire browsers, same results. I just can't figure out why there is so much delay between the http_sent() functions. It appears that this is somehow related to the lwip either not sending the tcp_write()/tcp_output() immediately or not processing the response packets quickly (or maybe a combination of both). At any rate it appears that httpd module can only serve up one chunk of the file about every 200msec. If you think of anything else please let me know. Rick
----- Original Message ----- From: Bill Auerbach To: 'Rick Culver' ; 'Mailing list for lwIP users' Sent: Friday, April 24, 2009 9:56 AM Subject: RE: [lwip-users] httpd slow response Ok. Than as Simon pointed out - the tcp_output avoids Nagle. I followed the contrib/apps httpd example and without tcp_output calls I needed TF_NODELAY. Which is right? I would hope that an lwIP contrib example would show the correct way to implement something. Bill From: [email protected] [mailto:[email protected]] On Behalf Of Rick Culver Sent: Friday, April 24, 2009 10:08 AM To: Bill Auerbach; 'Mailing list for lwIP users' Subject: Re: [lwip-users] httpd slow response Bill, I will try this in the accept call back and advise the results. The httpd.c module we are using is one that was supplied by Luminary Micro with their function library. It was modified from the one provided in contrib/apps to include some SSI functionality (which we have disabled). Basically the "send_data" function includes a call to tcp_output() just before the final return if any data was sent. Rick ----- Original Message ----- From: Bill Auerbach To: 'Rick Culver' ; 'Mailing list for lwIP users' Sent: Friday, April 24, 2009 7:41 AM Subject: RE: [lwip-users] httpd slow response Rick, I did this in the accept callback. I haven't seen an lwipopts method to do this. Which httpd server? The one in lwIP contrib/apps doesn't have the tcp_output you mention. Bill. From: [email protected] [mailto:[email protected]] On Behalf Of Rick Culver Sent: Friday, April 24, 2009 8:23 AM To: Bill Auerbach; 'Mailing list for lwIP users' Subject: Re: [lwip-users] httpd slow response Bill, Thanks for the prompt response. That would make sense to me. Where/how would I include this in the code? Do you know if there is a way to change this in the lwipopt.h file? I do see that the httpd server does include the tcp_output() function write after a tcp_write(), would that not negate the nagle delay anyway? What do you think? Rick ----- Original Message ----- From: Bill Auerbach To: 'Rick Culver' ; 'Mailing list for lwIP users' Sent: Thursday, April 23, 2009 5:07 PM Subject: RE: [lwip-users] httpd slow response Raw API doesn't disable Nagle. I found things to be faster if I do so: pcb->flags |= TF_NODELAY; // Disable Nagle Bill From: [email protected] [mailto:[email protected]] On Behalf Of Rick Culver Sent: Thursday, April 23, 2009 4:05 PM To: [email protected] Subject: [lwip-users] httpd slow response I am using lwip with raw API and the httpd web server. I noticed that when serving up larger files that the response seemed extremely slow. The http_sent() callback is used to send each new chunk of the file being served and I discovered that it is taking about 175msec between the http_sent() callbacks. What could be causing this huge delay in response? Any ideas would could be wrong and/or how we can speed up this otherwise slow server?
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