From 2d161e298d7e0605fac08e574f2a03fbd49e58e0 Mon Sep 17 00:00:00 2001 From: rodri Date: Sat, 7 Dec 2024 17:19:48 +0000 Subject: new tool: chrono (wip) --- nanosec.c | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) create mode 100644 nanosec.c (limited to 'nanosec.c') diff --git a/nanosec.c b/nanosec.c new file mode 100644 index 0000000..1301e9f --- /dev/null +++ b/nanosec.c @@ -0,0 +1,38 @@ +#include +#include +#include + +/* + * nsec() is wallclock and can be adjusted by timesync + * so need to use cycles() instead, but fall back to + * nsec() in case we can't + */ +uvlong +nanosec(void) +{ + static uvlong fasthz, xstart; + uvlong x, div; + + if(fasthz == ~0ULL) + return nsec() - xstart; + + if(fasthz == 0){ + if(_tos->cyclefreq){ + cycles(&xstart); + fasthz = _tos->cyclefreq; + } else { + xstart = nsec(); + fasthz = ~0ULL; + fprint(2, "cyclefreq not available, falling back to nsec()\n"); + fprint(2, "you might want to disable aux/timesync\n"); + return 0; + } + } + cycles(&x); + x -= xstart; + + /* this is ugly */ + for(div = 1000000000ULL; x < 0x1999999999999999ULL && div > 1 ; div /= 10ULL, x *= 10ULL); + + return x / (fasthz / div); +} -- cgit v1.2.3