Messages in this thread | | | Date | Tue, 26 Nov 1996 18:33:03 -0500 (EST) | From | "Richard B. Johnson" <> | Subject | Re: TCP/IP Checksumming |
| |
On Tue, 26 Nov 1996, Heiko Schroeder wrote:
> > Hmmm. The values below show quite the opposite. It is not that > difficult to fold the carries back, and what is more important, it > is done only once, not for every word accessed. > > Here are the measured values for some of the functions used: > > csum_partial: sum = 1a8a, min cycles 1406 > csum_simple: sum = 1a8a, min cycles 6846 > csum_opt: sum = 1a8a, min cycles 2455 > csum_opt32: sum = 1a8a, min cycles 1434 > csum_c: sum = 1a8a, min cycles 2626 > > csum_partial is the original Linux version. > csum_simple is the simple function using lodsw and loop, csum_opt is the > function that was best in the MS-DOS tests. csum_opt32 is csum_opt > changed to use 32-Bit memory accesses. And for comparison, there is > a C version of the checksumming algorithm in csum_c.
I don't understand. These numbers are not at all like I get in 32-bit mode, flat-model, writing results to the UART, with no interrupts.
I'll get back to you later. I have to take a work-break.
Cheers, Dick Johnson -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Richard B. Johnson Project Engineer Analogic Corporation Voice : (508) 977-3000 ext. 3754 Fax : (508) 532-6097 Modem : (508) 977-6870 Ftp : ftp@boneserver.analogic.com Email : rjohnson@analogic.com, johnson@analogic.com Penguin : Linux version 2.1.13 on an i586 machine. Warning : It's hard to remain at the trailing edge of technology. -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
| |