1 files changed, 48 insertions, 5 deletions
diff --git a/indra/llcommon/lltimer.cpp b/indra/llcommon/lltimer.cpp
index 7570420d2c..2c34608064 100644
--- a/indra/llcommon/lltimer.cpp
+++ b/indra/llcommon/lltimer.cpp
@@ -83,15 +83,20 @@ void ms_sleep(U32 ms)
 {
 	Sleep(ms);
 }
+
+U32 micro_sleep(U64 us, U32 max_yields)
+{
+    // max_yields is unused; just fiddle with it to avoid warnings.
+    max_yields = 0;
+    ms_sleep(us / 1000);
+    return 0;
+}
 #elif LL_LINUX || LL_SOLARIS || LL_DARWIN
-void ms_sleep(U32 ms)
+static void _sleep_loop(struct timespec& thiswait)
 {
-	long mslong = ms; // tv_nsec is a long
-	struct timespec thiswait, nextwait;
+	struct timespec nextwait;
 	bool sleep_more = false;
 
-	thiswait.tv_sec = ms / 1000;
-	thiswait.tv_nsec = (mslong % 1000) * 1000000l;
 	do {
 		int result = nanosleep(&thiswait, &nextwait);
 
@@ -127,6 +132,44 @@ void ms_sleep(U32 ms)
 		}
 	} while (sleep_more);
 }
+
+U32 micro_sleep(U64 us, U32 max_yields)
+{
+    U64 start = get_clock_count();
+    // This is kernel dependent.  Currently, our kernel generates software clock
+    // interrupts at 250 Hz (every 4,000 microseconds).
+    const U64 KERNEL_SLEEP_INTERVAL_US = 4000;
+
+    S32 num_sleep_intervals = (us - (KERNEL_SLEEP_INTERVAL_US >> 1)) / KERNEL_SLEEP_INTERVAL_US;
+    if (num_sleep_intervals > 0)
+    {
+        U64 sleep_time = (num_sleep_intervals * KERNEL_SLEEP_INTERVAL_US) - (KERNEL_SLEEP_INTERVAL_US >> 1);
+        struct timespec thiswait;
+        thiswait.tv_sec = sleep_time / 1000000;
+        thiswait.tv_nsec = (sleep_time % 1000000) * 1000l;
+        _sleep_loop(thiswait);
+    }
+
+    U64 current_clock = get_clock_count();
+    U32 yields = 0;
+    while (    (yields < max_yields)
+            && (current_clock - start < us) )
+    {
+        sched_yield();
+        ++yields;
+        current_clock = get_clock_count();
+    }
+    return yields;
+}
+
+void ms_sleep(U32 ms)
+{
+	long mslong = ms; // tv_nsec is a long
+	struct timespec thiswait;
+	thiswait.tv_sec = ms / 1000;
+	thiswait.tv_nsec = (mslong % 1000) * 1000000l;
+    _sleep_loop(thiswait);
+}
 #else
 # error "architecture not supported"
 #endif