![]() | |||||||||||
Messages in this thread |
H. Peter Anvin a écrit : > Jeremy Fitzhardinge wrote: >> H. Peter Anvin wrote: >>> Sounds like it would need a device which can be waited upon for changes. >> >> A vdso-like shared page could have a futex in it. > > Yes, but a futex couldn't be waited upon with a bunch of other things as > part of a poll or a select. The cost of reading the information is > minimal. > There is one thing that always worried me. Intel & AMD manuals make clear that mixing data and program in the same page is bad for performance. In particular, x86_64 vsyscall put jiffies and other vsyscall_gtod_data_t right in the midle of code. That is certainly not wise. A probably sane implementation should use two pages, one for code, one for data. - 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/ | ||||||||||
| Last update: 2007-04-04 07:13 [from the cache] ©2003-2008 | |||||||||||