Messages in this thread | | | From | Andy Lutomirski <> | Date | Sat, 1 Feb 2014 09:10:51 -0800 | Subject | Re: [PATCH] x86: Remove hpet vclock support |
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On Sat, Feb 1, 2014 at 7:43 AM, Clemens Ladisch <clemens@ladisch.de> wrote: > Andy Lutomirski wrote: >> The HPET is so amazingly slow that this is barely a win. > > What happens on CPUs where the TSC cannot be used for the clock?
vclock_gettime, etc will fall back to using syscalls, just like they would on systems using the PIT timer.
> >> it scares me a tiny bit to map a piece of crappy hardware where every >> userspace program can poke at it (even if said poking is read-only). >> Let's just remove it. > > So this mapping is a backdoor to bypass the restrictions on /dev/hpet? ;-) >
Yes, except that it's read-only.
At some point, someone will probably want to run code in a sandbox that can't tell time at all. That will be messy, but this is a decent first little step.
--Andy
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