Am Donnerstag, 26. Mai 2016, 22:14:29 schrieb Theodore Ts'o: Hi Theodore, > On Thu, May 26, 2016 at 08:49:39PM +0200, Stephan Mueller wrote: > > Using the kernel crypto API one can relieve the CPU of the crypto work, if > > a hardware or assembler implementation is available. This may be of > > particular interest for smaller systems. So, for smaller systems (where > > kernel bloat is bad, but where now these days more and more hardware > > crypto support is added), we must weigh the kernel bloat (of 3 or 4 > > additional C files for the basic kernel crypto API logic) against > > relieving the CPU of work. > > There are a number of caveats with using hardware acceleration; one is > that many hardware accelerators are optimized for bulk data > encryption, and so key scheduling, or switching between key schedules, > can have a higher overhead that a pure software implementation. As a followup: I tweaked the DRBG side a bit to use the full speed of the AES- NI implementation. With that tweak, the initial finding does not apply any more. I depending on the request size, I now get more than 800 MB/s (increase by more than 450% compared to the initial implementation) from the AES-NI implementation. Hence, the frequent key schedule update seems to be not too much of an issue. Ciao Stephan -- To unsubscribe from this list: send the line "unsubscribe linux-crypto" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
