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RC4 Code Achieves 319 MB/s On AMD64 Opteron

Posted by timothy on from the even-more-thingy dept.

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."

4 of 177 comments (clear)

  1. until by iamnotacrook · · Score: 4, Insightful

    amd decides to provide a compiler for its chip, optimization will always be behind intel (who do. for linux also).

    1. Re:until by isometrick · · Score: 4, Insightful

      I agree, to an extent. It's been said that Intel's compiler can outdo GCC in some performance benchmarks.

      GCC is no slouch though, and obviously Intel is performing some tricks that could also be implemented by GCC.

      I think it'd be a great move for AMD to work WITH GNU to optimize 64-bit AMD code from GCC.

      Seems like Intel is more prone to keeping secrets when it comes to processors. Maybe this is (yet another) way for AMD to give them a run for their money.

  2. well... by mx.2000 · · Score: 4, Insightful

    "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."

    well, maybe in some areas.
    Since this is a cipher, it obviously helps a lot when you can work on 64-Bit chunks of data instead of 32-Bit.

    The same speedup can probably be seen with applications that use numbers larger than 32b (or 64b for floats), since the number of operations necessary will essentially halve.

    But other than that, I don't see much room for huge speedups.

  3. Optimization First, Features Second by Space_Soldier · · Score: 4, Insightful

    I wish that every software company would put optimization first and features second. This way, we would not have to buy computers every few years. They can potentially last much longer.