Re: [Cfrg] Timing of libsodium, curve25519-donna, MSR ECCLib, and openssl-master

[Andrey Jivsov <[e-mail]>]

Michael Hamburg's question about hyperthreading made me think what kind 
of performance I can actually get on the whole CPU, as opposed to a 
single core?

I confirmed that, using the Curve25519 as an example, the 
single-threaded op/sec value can be multiplied by the number of cores to 
arrive at the total count.

Which gives us over 60,000 256-bit variable base scalar multiplications 
on a whole CPU. Recall that my reported number was 15764.3 op/sec.

To perform the measurement I wrapped the curve25519-donna code into the 
multithreaded code.

As the prints below show, the op/sec number, per thread, stays at ~15000 
level, deteriorating slightly, until the number of threads reaches the 
number of cores. The total operation count per CPU peaks at the number 
of threads equal the number of cores and then stays constant for higher 
number of threads. (actually, it peaks at the number of cores + 1, but 
that's a small increase).


Prints from the program follow. The diff: 
https://github.com/brainhub/curve25519-donna/commit/8fe32587444b9be3b9ec06cb2334a2cd3fc356cd.

Waiting in thread 1 ...
thread 1: 15616.2 op/sec in 6 sec
Total for CPU: 15616.2 op/sec

Waiting in thread 1 ...
Waiting in thread 2 ...
thread 1: 15221 op/sec in 7 sec
thread 2: 15224.6 op/sec in 7 sec
Total for CPU: 30445.5 op/sec

Waiting in thread 1 ...
Waiting in thread 2 ...
Waiting in thread 3 ...
thread 1: 14950.4 op/sec in 7 sec
thread 2: 14962.4 op/sec in 7 sec
thread 3: 14959.9 op/sec in 7 sec
Total for CPU: 44872.7 op/sec

Waiting in thread 1 ...
Waiting in thread 2 ...
Waiting in thread 3 ...
Waiting in thread 4 ...
thread 1: 14900.6 op/sec in 7 sec
thread 2: 14960.9 op/sec in 7 sec
thread 3: 14937.9 op/sec in 7 sec
thread 4: 14308.3 op/sec in 7 sec
Total for CPU: 59107.7 op/sec

Waiting in thread 4 ...
Waiting in thread 5 ...
Waiting in thread 3 ...
Waiting in thread 1 ...
Waiting in thread 2 ...
thread 1: 12298.4 op/sec in 8 sec
thread 2: 13157.2 op/sec in 8 sec
thread 3: 12187.7 op/sec in 8 sec
thread 4: 11612.9 op/sec in 9 sec
thread 5: 11201.8 op/sec in 9 sec
Total for CPU: 60457.9 op/sec

... and there is no improvement beyond 5 threads.