On Thursday, July 31, 2014 11:05:22 PM Jouni Malinen wrote:

On Wed, Jul 30, 2014 at 08:59:33PM +0200, Christian Lamparter wrote:

quoted

If you have disabled rx-decrypt logic of ath10k, then why isn't _aesni_dec1
or aes_decrypt listed in the perf top result? I think they should be. Have you
removed them from the "perf top results" or are they really absent 
altogether? 

Because, from this perf result, it looks like your CPU is not burden by the
incoming RX at all?! Instead it is busy with the encryption of frames
it will be transmitting (in case of tcp, this could be tcp acks).

Keep in mind that this is CCMP, i.e., AES in CCM (Counter with CBC-MAC)
mode. The CCM mode uses only the block cipher encryption function, i.e.,
you won't be seeing aes_decrypt or _aesni_dec1 for this even on the RX
path (AES encryption operations are used to generate the key stream
blocks for CCM decryption).

Yes, I remember this detail/the old days (before 3.12/3.13?). Back then
ieee80211_aes_ccm_decrypt did exactly that. But these semantic pitfalls
were taken care of by the following commit:

commit 7ec7c4a9a686c608315739ab6a2b0527a240883c (from wireless-testing.git)
Author: Ard Biesheuvel [off-list ref]
Date:   Thu Oct 10 09:55:20 2013 +0200

  mac80211: port CCMP to cryptoapi's CCM driver
   
  Use the generic CCM aead chaining mode driver rather than a local
  implementation that sits right on top of the core AES cipher.
  
  This allows the use of accelerated implementations of either
  CCM as a whole or the CTR mode which it encapsulates.
  [...]

Regards
Christian