On Tuesday, August 12, 2014 11:34:59 AM Ben Greear wrote: > On 08/10/2014 06:44 AM, Christian Lamparter wrote: > > On Thursday, August 07, 2014 10:45:01 AM Ben Greear wrote: > >> On 08/07/2014 07:05 AM, Christian Lamparter wrote: > >>> Or: for every 16 Bytes of payload there is one fpu context save and > >>> restore... ouch! > >> > >> Any idea if it would work to put the fpu_begin/end a bit higher > >> and do all those 16 byte chunks in a batch without messing with > >> the FPU for each chunk? > > > > It sort of works - see sample feature patch for aesni-intel-glue > > (taken from 3.16-wl). Older kernels (like 3.15, 3.14) need: > > "crypto: allow blkcipher walks over AEAD data" [0] (and maybe more). > > > > The FPU save/restore overhead should be gone. Also, if the aesni > > instructions can't be used, the implementation will fall back > > to the original ccm(aes) code. Calculating the MAC is still much > > more expensive than the payload encryption or decryption. However, > > I can't see a way of making this more efficient without rewriting > > and combining the parts I took from crypto/ccm.c into an several, > > dedicated assembler functions. > > Without encryption, I see download rate of around 400 - 420Mbps. > > So, your patch looks like a good improvement to me, and I'll be > happy to test further patches if you happen to do those assembler > optimizations you talk about above. Maybe, that will depend on what the results for: "wpa2, *HW*-crypt, download, udp" are. > Let me know if you would like more/different performance > stats. There's a test bench tool (tcrypt) to measure the performance of any cipher. It would be interesting to know what the performance/throughput it can produce without the overhead of any application. [Yep, I'm making a small patch to test that, but not before Saturday next week]. > Here is perf top of open authentication, download, UDP: > > Using WPA2, sw-crypt, download, UDP: > > Samples: 52K of event 'cycles', Event count (approx.): 13162827574 > 24.78% btserver [.] 0x00000000000c598c Is btserver your "udp download" test application? What does it do, as it is accounting for nearly 25%? Regards Christian -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
