[ECOS] TCP/IP checksum routine performance

Andrew Lunn andrew.lunn@ascom.ch
Fri Apr 28 00:25:00 GMT 2000


> I've been playing with various system performance issues for
> the past couple days. According to the results of running
> nc_test_slave, the checksum routine (in_cksum.c) is taking more
> time than all of the other instrumented routines combined.

Once you have finish your assembly code could you contribute it back
please? I would be interested in using it on my ARM platform.

It may also be worth looking at the Linux implementation. The ARM CRC
routines are in assembly. It may give you some ideas for optimisation.

> So, the executive summary for ARM users is: you can probably
> improve your TCP/IP performance noticably by compiling
> in_cksum.c with optimization turned off.

:-)

Would you guess this is to do with endianess? Is the assembly doing
lots of word order changes? Maybe this is a general issue for the ARM
compiler. It could be interesting to run tm_basic with different
levels of optimisation and see what happens.

        Andrew




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