andrea@suse.de said:
> What I suggested is an arch specific syscall to shutdown vsyscalls
> enterely for the current task and its childs,
Then I misunderstood.
> the vsyscall will call
> into the real syscall with sysenter, and you will be able to
> revirtualize gettimeofday/time like you do on x86 with ptrace.
And the task-specific fixmap entry would point to a page that makes the normal
system call?
> what do you mean that uml needs the vsyscalls more than the other
> archs?
Because its system calls are much slower than the host's. It would benefit
more from vsyscalls.
> I much prefer you to keep trapping the gettimeofday and time with
> ptrace after shutting down the vsyscalls for the current task, it's so
> much cleaner.
And so much slower.
> The overhead of ptrace cannot be your point, if that
> overhead is a showstopper uml isn't an option in the first place.
I don't plan on using ptrace forever. That overhead is going to shrink, and
vsyscalls are one way to make it shrink.
I intend to make UML perform by grabbing whatever improvements from wherever
I can get them, and if I can't get vsyscalls because they're not virtualizable,
then, from my point of view, their design is broken.
Jeff
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This archive was generated by hypermail 2b29 : Wed Oct 23 2002 - 22:00:49 EST