I have been running some tests on my windows 32 bit application which is using the latest libcurl dlls downloaded from curl.haxx.se.

What I see is its performance slightly slower than in Cygwin. All performance measured on 10Gig link.

I took the sample code to upload a file from src/examples for http PUT, and compiled (identical code) it on
    1. Cygwin
    2. Visual Studio 2008.

Here is what I see when I PUT a large file (i.e. 100 MB):

Cygwin version is able to send data faster. This is confirmed by the presence of back-to-backk jumbo frames of 16KB each, as it is
also the maximum read size in libcurl, reaching upto 65KB -- the maximum windows of TCP.

In Cygwin, these back to back frames would later follow an ack from the other side (i.e. server).

Whereas with windows compilation, the jumbo frames rarely stack up. I will never see 4 16KB packets going out back to back, even
though the TCP window is wide open then!

I also ran a python program over the same file in Cygwin, and that also confirmed the back to back jumbo frames going out.

Would anybody like to offer me their experience/suggestions please.

I have not compiled libcurl dlls myself, and so am not aware if any compile options might be affecting all this!

Best wishes,

-CS

      
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Received on 2010-05-28