----Original Message---- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Roger Cover Sent: Wednesday, April 18, 2007 1:03 PM To: Mailing list for lwIP users Subject: RE: [lwip-users] Optimizations forapplications requiring limitedfunctionality.
> Greetings All, > > I have made a discovery about my problem. I upgraded to version 9.1 > of the Xilinx EDK at the same time I upgraded to lwIP 1.2.0. This EDK > upgrade changed the GNU compiler suite that I am using. The new > version of the compiler is the source of my problem. It generates > much less efficient code, even with optimizations turned up. > > The time spent in the lwIP library (for my UDP transfer) is now only > 4.2% of the total transfer time. The bulk of the transfer time is in > the Xilinx driver code (82%). The suggestions I received (thanks to > Frédéric Bernon) to remove unused options from lwIP did reduce the > time used by the lwIP library. Unfortunately, that was not my > problem. > > I am not sure why the new version of the compiler is so much less > efficient. The old compiler produced code that transferred my > 33554432-byte dataset in 5.8 seconds. The code produced with new > compiler takes 8.8 seconds (62.5% of the throughput performance). I > will be looking into that. > > My mistake was in presuming that the same driver source code would > produce the same executable code under EDK 8.1 and EDK 9.1. That led > me to the incorrect conclusion that the difference in performance was > in the new lwIP library. Thank you all for your help. > > Regards, > Roger W. Cover > Hi Roger, Xilinx upgraded their compiler from GCC 3.4.1 to 4.1.1 between EDK 8.2 and 9.1. If you are confident the compiler is creating less efficient code, I recommend you open a case with them. I have no experience with the new EDK, but I suspect the new compiler may not be fully optimized yet. Matthew _______________________________________________ lwip-users mailing list [email protected] http://lists.nongnu.org/mailman/listinfo/lwip-users
