Hi, Reviving this topic, since I think it's interesting in the presence of persistent memory engines that rely heavily on optimized memcpy to be fast. Similar to how we have --crctest, I added --memcpytest. Very basic, just wanted to get the ball rolling. Basically it just copies between two 32MB chunks, using whatever implementation you would like, and in increments of some defined size. This is what it spits out on my laptop: memcpy 8 bytes: 3360.94 MiB/sec 16 bytes: 4363.47 MiB/sec 96 bytes: 6804.46 MiB/sec 128 bytes: 6391.39 MiB/sec 256 bytes: 6571.09 MiB/sec 512 bytes: 6962.77 MiB/sec 2048 bytes: 6212.73 MiB/sec 8192 bytes: 6465.14 MiB/sec 131072 bytes: 6412.24 MiB/sec 262144 bytes: 6607.03 MiB/sec 524288 bytes: 6372.90 MiB/sec memmove 8 bytes: 2503.90 MiB/sec 16 bytes: 4311.81 MiB/sec 96 bytes: 6734.74 MiB/sec 128 bytes: 6080.16 MiB/sec 256 bytes: 6162.92 MiB/sec 512 bytes: 7309.80 MiB/sec 2048 bytes: 6931.94 MiB/sec 8192 bytes: 6878.97 MiB/sec 131072 bytes: 6787.05 MiB/sec 262144 bytes: 6877.77 MiB/sec 524288 bytes: 6695.26 MiB/sec simple 8 bytes: 1813.59 MiB/sec 16 bytes: 2191.63 MiB/sec 96 bytes: 7360.76 MiB/sec 128 bytes: 7192.63 MiB/sec 256 bytes: 7340.00 MiB/sec 512 bytes: 7158.04 MiB/sec 2048 bytes: 7495.96 MiB/sec 8192 bytes: 7315.30 MiB/sec 131072 bytes: 7565.82 MiB/sec 262144 bytes: 7410.95 MiB/sec 524288 bytes: 7537.09 MiB/sec which is kind of depressing, since the fastest for larger sizes is the very dumb and basic implementation that you'll find in any text book under the section of "my first memcpy". Anyway, for evaluating implementations, we need a way to test them, and now we have. I'll be happy to take input/patches on the test itself. -- Jens Axboe -- To unsubscribe from this list: send the line "unsubscribe fio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
