Messages in this thread |  | | Date | Wed, 11 Aug 2004 08:25:10 -0700 | From | Chris Wright <> | Subject | Re: [PATCH] [LSM] Rework LSM hooks |
| |
* David Mosberger (davidm@napali.hpl.hp.com) wrote: > >>>>> On Tue, 10 Aug 2004 16:31:12 -0400 (EDT), James Morris <jmorris@redhat.com> said: > > James> On Tue, 10 Aug 2004, Chris Wright wrote: > >> Thanks, James. Since these are the only concrete numbers and > >> they are in the noise, I see no compelling reason to change to > >> unlikely(). > > James> There may be some way to make it ia64 specific. Is it a cpu > James> issue, or compiler? > > I'm pretty sure the "unlikely()" part could be dropped with little/no > downside. The part that's relatively expensive (10 cycles when > mispredicted) is the indirect call. GCC doesn't handle this well on > ia64 and as a result, most indirect calls are mispredicted. > > An alternative solution might be to have a call_likely() macro, where > you could predict the most likely target of an indirect call. Perhaps > that could help other platforms as well.
Hmm, the pointers are generally quite static, set once near boot time typically, and that's it. Seems like a plausible win. Do you have an example of what call_likely() would look like?
thanks, -chris -- Linux Security Modules http://lsm.immunix.org http://lsm.bkbits.net - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
|  |