diff --git a/sources/common-dylan/library.dylan b/sources/common-dylan/library.dylan index a78ac4dca..15c9c221b 100644 --- a/sources/common-dylan/library.dylan +++ b/sources/common-dylan/library.dylan @@ -47,7 +47,8 @@ define module simple-timers timer-start, timer-stop, timer-accumulated-time, - timer-running?; + timer-running?, + microsecond-counter; end module simple-timers; define module byte-vector diff --git a/sources/common-dylan/tests/common-dylan-test-suite.lid b/sources/common-dylan/tests/common-dylan-test-suite.lid index 587265d5f..5ab5c4715 100644 --- a/sources/common-dylan/tests/common-dylan-test-suite.lid +++ b/sources/common-dylan/tests/common-dylan-test-suite.lid @@ -12,6 +12,7 @@ Files: library streams byte-vector machine-words + timers-tests transcendentals regressions threads/simple-locks diff --git a/sources/common-dylan/tests/library.dylan b/sources/common-dylan/tests/library.dylan index 44f971541..48ee72b0d 100644 --- a/sources/common-dylan/tests/library.dylan +++ b/sources/common-dylan/tests/library.dylan @@ -40,6 +40,7 @@ define module common-dylan-test-suite use simple-format; use simple-random; use simple-profiling; + use simple-timers; use file-system, import: { file-exists? }; use operating-system, diff --git a/sources/common-dylan/tests/timers-tests.dylan b/sources/common-dylan/tests/timers-tests.dylan new file mode 100644 index 000000000..b0a135643 --- /dev/null +++ b/sources/common-dylan/tests/timers-tests.dylan @@ -0,0 +1,14 @@ +Module: common-dylan-test-suite + + +define test test-microsecond-counter () + let t1 = microsecond-counter(); + sleep(0.1); + let t2 = microsecond-counter(); + let diff = t2 - t1; + // I need slop to be at least 5200 on my macOS M3 Pro. Be more generous than + // that since the main point is simply to exercise the function at all. --cgay + let slop = 50_000; + assert-true(diff >= (100_000 - slop) & diff < (100_000 + slop), + diff); +end test; diff --git a/sources/common-dylan/timers.dylan b/sources/common-dylan/timers.dylan index 0535bd899..78280c3aa 100644 --- a/sources/common-dylan/timers.dylan +++ b/sources/common-dylan/timers.dylan @@ -111,3 +111,18 @@ define inline function %timer-diff-times values(seconds, microseconds) end if end; + +// We use a microsecond counter rather than nanoseconds because implementations +// may legitimately return a time since some arbitrary epoch rather than, say, +// the machine uptime, and that could easily overflow given only 61 usable +// bits. Ex: In 2024, the nanos since 1970-01-01 already uses 61 bits. +define function microsecond-counter () => (microseconds :: ) + let (sec :: , nano :: ) + = %timer-current-time(); + // I think coerce...(u%-(sec, 0)) is faster than as-unsigned(, sec) + // due to the latter causing a fully dynamic gf method dispatch. Is there a + // better way? + let seconds :: = coerce-machine-word-to-integer(u%-(sec, 0)); + let microseconds :: = coerce-machine-word-to-integer(u%divide(nano, 1000)); + seconds * 1_000_000 + microseconds +end function;