Messages in this thread | | | Date | Mon, 18 Sep 2006 17:06:50 +0200 | From | Ingo Molnar <> | Subject | Re: Sysenter crash with Nested Task Bit set |
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* Linus Torvalds <torvalds@osdl.org> wrote:
> And sysenter really is very special because of the weak trap > semantics. Damn. We could either fix it in the sysenter code-path, or > in the task-switch one, and both of them are timing-critical, but task > switching perhaps just a tad less so.
agreed. Context-switching is 10 times less frequent on most workloads than syscalls, so if it takes 10 cycles in the context-switch path to eliminate a 1 cycle overhead in the syscall-entry path then we are still break-even on average. In this case the overhead is similar i think, so the switch_to() fix is preferable.
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