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On Tue, 17 Dec 2002, Linus Torvalds wrote: > > How about this patch? Instead of making a per-cpu trampoline, write to > > the msr during each context switch. > > I wanted to avoid slowing down the context switch, but I didn't actually > time how much the MSR write hurts you (it needs to be conditional, > though, I think). this is the solution i took in the original vsyscall patches. The syscall entry cost is at least one factor more important than the context-switch cost. The MSR write was not all that slow when i measured it (it was on the range of 20 cycles), and it's definitely something the chip makers should keep fast. Ingo - 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/ | |||||||||
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