On Fri, Oct 21, 2011 at 04:15:41PM +0200, Matthias-Christian Ott wrote: > On Fri, Oct 21, 2011 at 03:23:36PM +0200, Herbert Xu wrote: > > Matthias-Christian Ott <ott@xxxxxxxxx> wrote: > > > I did some experiments with af_alg and noticed that to be really > > > useful, it should indicate whether a certain algorithm is hardware > > > accelerated. I guess this has to be inferred by the priority of the > > > algorithm could be made available via a read-only socket option. Any > > > thoughts on this? > > > > > > I can imagine, an alternative approach and perhaps better approach > > > would be to measure the speed of the kernel provided algorithm against > > > a software implementation, but there are many other factors that could > > > influence the results. Therefore, it is perhaps better to just make > > > the assumption that hardware acceleration is faster which is made in > > > the kernel anyhow. > > > > You have to be careful to distinguish between hardware acceleration > > that is directly available to user-space (such as AESNI) and those > > that aren't. > > > > For the former it makes zero sense to go through the kernel as > > you'll only make it slower. The latter case is the reason why > > this interface exists. > > This is why I didn't consider hardware acceleration that is directly > available to user-space in the first place (I'm not aware of anything > except CPUs that is usable this way). So the question remains whether > e.g. the AES implementation provided through af_alg by the kernel is > faster (and thus most likely hardware accelerated) than a software > implementation. Since the kernel seems to make the assumption that > hardware acceleration is faster, I asked whether it would be possible to > pass this information to user-space as well. Ignore that e-mail. The the recent user configuration patches by Stefan Klassert seem to expose the algorithm's priority via CRYPTOCFGA_PRIORITY_VAL. This should solve my problem, provided that the patches will be included. Regards, Matthias-Christian -- 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
