X-Git-Url: https://git.kernel.dk/?p=fio.git;a=blobdiff_plain;f=gettime.c;h=b1431f329bec2e3ef9e32439035d896e9f8545ca;hp=2753faecb02d0596b1898346a46bf7f1d9e44873;hb=814452bd47e0f2bb4825b8042b664f32de0aff8d;hpb=01743ee1718e7ec4b16ae3e53c8f64900c6052cc

diff --git a/gettime.c b/gettime.c
index 2753faec..b1431f32 100644
--- a/gettime.c
+++ b/gettime.c
@@ -6,10 +6,17 @@
 #include <sys/time.h>
 
 #include "fio.h"
+#include "smalloc.h"
 
 #include "hash.h"
 
 static int clock_gettime_works;
+static struct timeval last_tv;
+static int last_tv_valid;
+
+static struct timeval *fio_tv;
+int fio_gtod_offload = 0;
+int fio_gtod_cpu = -1;
 
 #ifdef FIO_DEBUG_TIME
 
@@ -114,7 +121,10 @@ void fio_gettime(struct timeval *tp, void fio_unused *caller)
 
 	gtod_log_caller(caller);
 #endif
-	if (!clock_gettime_works) {
+	if (fio_tv) {
+		memcpy(tp, fio_tv, sizeof(*tp));
+		return;
+	} else if (!clock_gettime_works) {
 gtod:
 		gettimeofday(tp, NULL);
 	} else {
@@ -128,4 +138,29 @@ gtod:
 		tp->tv_sec = ts.tv_sec;
 		tp->tv_usec = ts.tv_nsec / 1000;
 	}
+
+	/*
+	 * If Linux is using the tsc clock on non-synced processors,
+	 * sometimes time can appear to drift backwards. Fix that up.
+	 */
+	if (last_tv_valid) {
+		if (tp->tv_sec < last_tv.tv_sec)
+			tp->tv_sec = last_tv.tv_sec;
+		else if (last_tv.tv_sec == tp->tv_sec &&
+			 tp->tv_usec < last_tv.tv_usec)
+			tp->tv_usec = last_tv.tv_usec;
+	}
+	last_tv_valid = 1;
+	memcpy(&last_tv, tp, sizeof(*tp));
+}
+
+void fio_gtod_init(void)
+{
+	fio_tv = smalloc(sizeof(struct timeval));
+	assert(fio_tv);
+}
+
+void fio_gtod_update(void)
+{
+	gettimeofday(fio_tv, NULL);
 }