How can I interpret openssl speed output?

Question

I ran openssl speed on my Ubuntu computer. Some results:

Doing md4 for 3s on 16 size blocks: 9063888 md4's in 3.00s
Doing md4 for 3s on 64 size blocks: 7105157 md4's in 3.00s
Doing md4 for 3s on 256 size blocks: 4507884 md4's in 3.00s
Doing md4 for 3s on 1024 size blocks: 1809773 md4's in 2.99s
Doing md4 for 3s on 8192 size blocks: 275679 md4's in 3.00s

What exactly those numbers mean?

1. what is 'Doing md4 for 3s' mean? does it mean do the whole test for 3 times/seconds?
2. what does '1809773 md4's in 2.99s' mean?
3. what does '8192 size blocks' mean?

The 'numbers' are in 1000s of bytes per second processed.
type             16 bytes     64 bytes    256 bytes   1024 bytes   8192 bytes
md4              47363.12k   151534.29k   382055.94k   615801.51k   747692.03k

And the above, last lines of openssl speed md4 output - what does they mean exactly?

Answer 1

While it could probably be worded better, it pretty much means what it says - run the md4 hash routine in a loop for 3 seconds with a 16 byte input. After 3 seconds, observe that we ran just a bit over 9 million iterations. That's about 144 million bytes processed, or 48 million bytes per second (where "million" means 10^6).