Messages in this thread | | | From | (Eric W. Biederman) | Subject | Re: [PATCH] Use uname not sysctl to get the kernel revision | Date | Wed, 12 Jul 2006 15:56:13 -0600 |
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Arjan van de Ven <arjan@infradead.org> writes:
> On Wed, 2006-07-12 at 15:23 -0600, Eric W. Biederman wrote: >> "H. Peter Anvin" <hpa@zytor.com> writes: >> >> > Jakub Jelinek wrote: >> >> On Wed, Jul 12, 2006 at 12:33:56PM -0700, Ulrich Drepper wrote: >> >>> Roland McGrath wrote: >> >>>> We could also put the uname info (modulo nodename) into the vDSO. >> >>> Or even better: real topology information. >> >> AND rather than OR would be even better. So glibc could find kernel >> >> version, etc. and topology in the vDSO cheaply. >> > >> > Wouldn't it make more sense for this to be in ELF tags, rather than the > vdso? >> > Another alternative, I guess, would be to put a pointer in the ELF tags, > which >> > may point into the vdso. >> >> Cheap and simple access to topology information would be interesting. >> >> Glibc just wants to know if our kernel is SMP so it can know if it is >> ok to busy wait for a bit waiting for a mutex. Or if busy waiting is >> a complete loss. > > > with current power management... busy waiting pretty much is a loss even > on UP
It is a short busy wait before falling asleep. I assume you mean busy wait is a loss even on SMP?
Eric
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