Re: comparison of the AF_ALG interface with the /dev/crypto

Herbert,

On Thu, Sep 01, 2011 at 10:14:45PM +0800, Herbert Xu wrote:

Phil Sutter [off-list ref] wrote:

quoted

chunksize       af_alg          cryptodev       (100 * cryptodev / af_alg)
--------------------------------------------------------------------------
512              4.169 MB/s      7.113 MB/s     171 %
1024             7.904 MB/s     12.957 MB/s     164 %
2048            13.163 MB/s     19.683 MB/s     150 %
4096            20.218 MB/s     26.960 MB/s     133 %
8192            27.539 MB/s     34.373 MB/s     125 %
16384           33.730 MB/s     39.997 MB/s     119 %
32768           37.399 MB/s     42.727 MB/s     114 %
65536           40.004 MB/s     44.660 MB/s     112 %

Are you maxing out your submission CPU? If not then you're testing
the latency of the interface, as opposed to the throughput.

Good point. So in order to also test the throughput, I've put my OpenRD
under load:

| stress -c 2 -i 2 -m 2 --vm-bytes 64MB

and ran the tests again:

chunksize       af_alg          cryptodev       (100 * cryptodev / af_alg)
--------------------------------------------------------------------------
512              0.618 MB/s      1.14 MB/s      184 %
1024             1.258 MB/s      2.28 MB/s      181 %
2048             2.453 MB/s      4.39 MB/s      179 %
4096             4.540 MB/s      7.76 MB/s      171 %
8192             7.981 MB/s     11.67 MB/s      146 %
16384           12.543 MB/s     14.08 MB/s      112 %
32768           13.139 MB/s     14.46 MB/s      110 %
65536           14.254 MB/s     15.55 MB/s      109 %

So that means cryptodev-linux is superior in throughput as well as
latency, right? Or is it the lower latency of the interface causing the
higher throughput?

Greetings, Phil