From aa3fd7ba28ee366eb0f037fc98ca696ffb3ed38c Mon Sep 17 00:00:00 2001
From: Bill Somerville <bill@classdesign.com>
Date: Wed, 10 Dec 2014 01:34:35 +0000
Subject: [PATCH] Remove gratuitous sleeps before function exits

Add sleep in tight wait loop to reduce CPU loading.
---
 lib/termios.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/lib/termios.c b/lib/termios.c
index e5f1f4b25..1133b63ec 100644
--- a/lib/termios.c
+++ b/lib/termios.c
@@ -1397,9 +1397,10 @@ int win32_serial_read( int fd, void *vb, int size )
           if (stat.cbInQue < index->ttyset->c_cc[VMIN])
             {
               /*
-                usleep(1000);
                 usleep(50);
               */
+              usleep(100);     /* don't hog the CPU while waiting */
+
               /* we should use -1 instead of 0 for disabled timeout */
               now = GetTickCount();
               if (index->ttyset->c_cc[VTIME] &&
@@ -3258,7 +3259,7 @@ int  win32_serial_select( int  n,  fd_set  *readfds,  fd_set  *writefds,
 		   this does happen.  loops ~twice on a 350 Mzh with
 		   usleep(1000000)
 		*/
-		usleep(10000);
+		/* usleep(10000); */
 		LEAVE( "serial_uselect" );
 		return(0);
 	}
@@ -3334,7 +3335,7 @@ int  win32_serial_select( int  n,  fd_set  *readfds,  fd_set  *writefds,
 	}
 end:
 	/*  You may want to chop this out for lower latency */
-	usleep(1000);
+	/* usleep(1000); */
 	LEAVE( "serial_select" );
 	return( 1 );
 timeout:
@@ -3361,7 +3362,7 @@ int  win32_serial_select( int  n,  fd_set  *readfds,  fd_set  *writefds,
 	ENTER( "serial_select" );
 	if ( fd <= 0 )
 	{
-		usleep(1000);
+		/* usleep(1000); */
 		return 1;
 	}
 	index = find_port( fd );
@@ -3376,7 +3377,7 @@ int  win32_serial_select( int  n,  fd_set  *readfds,  fd_set  *writefds,
 	}
 	while(!index->event_flag )
 	{
-		usleep(1000);
+		/* usleep(1000); */
 		return -1;
 	}