Quote from: ArtForz on March 24, 2011, 12:04:47 PM

According to sun, T2 can do "32 Gb/s/chip" for SHA-1
let's just assume it's as fast for SHA-256.
let's further assume it's magic and has 0 setup cost.
SHA256 block size is 512 bits, so 32Gb/s / 512 = 62.5M sha256 blocks/s
one bitcoinhash is 2 sha256 blocks, so 62.5M / 2 =
31.25Mhash/s.

Not bad for a crypto accel.
A $110 HD5770 does > 5x that.

I did find a student paper which measured the performance of the T2 here: http://cs.anu.edu.au/student/projects/10S2/Reports/Cody%20Christopher.pdf...and ArtForz really hit the nail on the head (like, freaky scarily on the head) compared to the experimental results. Seems like if you run 8 threads worth on a T2 (there's 8 hashing units on each T2 die, from what I can read), you would hit ~31.25Mhash/sec if you hash 8k of data.

Where the paper is a little unclear is if hashing 512 bits on the hardware is worthwhile, since it seems like the Sun supplied code will use the hardware if it's worth it. From section 4.2.1 in the paper, if we force the hardware to hash 512 bits, then we see that the speed of the hardware is only 1510.94kb/sec. This leads to a rate of 2.95M sha256 blocks/s, or 1.5Mhash/s.

Looks like the setup cost is prohibitive for small blocks, but for larger ones, it's negligible. Tradeoff for the T2 is around the 8k mark.