diff options
Diffstat (limited to 'winsup/cygwin/times.cc')
| -rw-r--r-- | winsup/cygwin/times.cc | 36 |
1 files changed, 25 insertions, 11 deletions
diff --git a/winsup/cygwin/times.cc b/winsup/cygwin/times.cc index e694d6875..4f4c39c92 100644 --- a/winsup/cygwin/times.cc +++ b/winsup/cygwin/times.cc @@ -1,7 +1,7 @@ /* times.cc Copyright 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, - 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 Red Hat, Inc. + 2005, 2006, 2007, 2008, 2009, 2010, 2011 Red Hat, Inc. This file is part of Cygwin. @@ -27,7 +27,17 @@ details. */ #include "cygtls.h" #include "ntdll.h" -hires_ms NO_COPY gtod; +/* Max allowed diversion in 100ns of internal timer from system time. If + this difference is exceeded, the internal timer gets re-primed. */ +#define JITTER (40 * 10000LL) + +/* TODO: Putting this variable in the shared cygwin region partially solves + the problem of cygwin processes not recognizing date changes when other + cygwin processes set the date. There is still an additional problem of + long-running cygwin processes becoming confused when a non-cygwin process + sets the date. Unfortunately, it looks like a minor redesign is required + to handle that case. */ +hires_ms gtod __attribute__((section (".cygwin_dll_common"), shared)); hires_ns NO_COPY ntod; @@ -565,7 +575,16 @@ hires_ms::nsecs () { if (!inited) prime (); - return systime_ns (); + + LONGLONG t = systime_ns (); + LONGLONG res = initime_ns + timeGetTime_ns (); + if (llabs (res - t) > JITTER) + { + inited = false; + prime (); + res = initime_ns + timeGetTime_ns (); + } + return res; } extern "C" int @@ -712,15 +731,10 @@ hires_ms::resolution () status = NtQueryTimerResolution (&coarsest, &finest, &actual); if (NT_SUCCESS (status)) - /* The actual resolution of the OS timer is a system-wide setting which - can be changed any time, by any process. The only fixed value we - can rely on is the coarsest value. */ - minperiod = coarsest; + minperiod = (DWORD) actual; else { - /* There's no good reason that NtQueryTimerResolution should fail - at all, but let's play it safe. Try to empirically determine - current timer resolution */ + /* Try to empirically determine current timer resolution */ int priority = GetThreadPriority (GetCurrentThread ()); SetThreadPriority (GetCurrentThread (), THREAD_PRIORITY_TIME_CRITICAL); @@ -823,7 +837,7 @@ clock_setres (clockid_t clk_id, struct timespec *tp) __seterrno_from_nt_status (status); return -1; } - minperiod = period; + minperiod = actual; period_set = true; return 0; } |