Emulate clock, times, and getrusage using the monotonic clock.
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Upcoming WASI snapshots omit the `PROCESS_CPUTIME` clock, since WASI has no inherent concept of processes, and since implementations which don't use a process for each instance don't have a way to implement it efficiently. However, `clock`, `times`, and `getrusage` are useful functions, so provide optional emulated version of them, using the `MONOTONIC` clock. This means these implementations will measure not just the program's own CPU time, but also time spent suspended while other programs are running. Due to this difference in behavior, put these implementations behind a flag. Users must pass `-D_WASI_EMULATED_PROCESS_CLOCK` and link with `-lwasi-emulated-process-clocks` to enable them.
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pchickey
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sbc100
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It would be nice to be able to simply use clock() without having to specify additional defines and libraries... On Windows, clock() already accounts for the amount of time spent waiting, so I'm not sure that the value of the extra warnings/errors in absence of the said define justify themselves... |
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Upcoming WASI snapshots omit the
PROCESS_CPUTIMEclock, since WASI hasno inherent concept of processes, and since implementations which don't
use a process for each instance don't have a way to implement it
efficiently.
However,
clock,times, andgetrusageare useful functions, soprovide optional emulated version of them, using the
MONOTONICclock.This means these implementations will measure not just the program's
own CPU time, but also time spent suspended while other programs are
running.
Due to this difference in behavior, put these implementations behind
a flag. Users must pass
-D_WASI_EMULATED_PROCESS_CLOCKand link with-lwasi-emulated-process-clocksto enable them.