RC4 Code Achieves 319 MB/s On AMD64 Opteron

Marc Bevand writes "This recent paper is about optimizing RC4 for AMD64 processors. A working implementation is provided. Its encryption/decryption throughput reaches 319 MB/s on a single AMD Opteron x44 processor running at 1.8 GHz. This makes it, as of today, the world's fastest RC4 symmetric cipher implementation for general purpose CPUs. As the author of this work, I would like to point out that many CPU-hungry applications have not been optimized for AMD64 yet. In other words: such speedups can be expected in other areas." An anonymous reader adds some figures for the old implementation: "Opteron 244 1.8 GHz (32-bit) 163 MB/s; Opteron 244 1.8 GHz (64-bit) 135 MB/s."

Comments

Optimisation is definately the key

[datajack]

I was initially disappointed with the performance of my Athlon64. CPU intensive 64bit code often seemed much slower than it's (heavily optimised) 32bit counterpart.

Every now & then I come across some code optimised for 64bit processors, and it just flies - as more & more stuff gets the treatment, it will be like upgradingin for free :)

Re:Somewhat OT, but...

[mczak]

AFAIK, the VIA's *only* do AES, as they're designed to make good VPN endpoints. This is cos some hefty AES subroutines are built into the hardware (with software drivers doing the rest).

True. VIA padlock (as they call it) can currently only do AES in hardware (and it can also generate true random numbers). The next VIA chip called C7 (C5J Esther) however should be able to also do SHA-1, SHA-256 and parts of RSA in hardware (I think it should be available first half of 2005). That's of course still a limited set of encryption algorithms, but it's certainly an improvement.

Re:until

[RupW]

Sorry it's not immediately obvious to me. Who are they?

AFAICR AMD paid SuSE to do the original work. I think the main developers were Jan Hubicka, the current x86-64 maintainer, and Andreas Jaeger. SuSE have a few more well-known GCC contributors: look at MAINTAINERS.