Attachment 13798 Details for Bug 14137 – scheduler patch

[patch] scheduler patch

94_the-smart-scheduler-itimer-currently-always-fires-af.patch (text/plain), 4.30 KB, created by Erik Andren on 2008-01-19 10:52:10 UTC

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Creator: Erik Andren

Created: 2008-01-19 10:52:10 UTC

Size: 4.30 KB

patch

obsolete

>>From 48e4d08e99de41047c6b6fde5ba9d12787881c23 Mon Sep 17 00:00:00 2001
>From: root <root@benny.jf.intel.com>
>Date: Sun, 28 Oct 2007 09:37:52 +0100
>Subject: [PATCH] The smart scheduler itimer currently always fires after each request
> (which in turn causes the CPU to wake out of idle, burning precious power).
> Rather than doing this, just stop the timer before going into the select()
> portion of the WaitFor loop. It's a cheap system call, and it will only get
> called if there's no more commands batched up from the active fd.
>
>This change also allows some of the functions to be simplified; setitimer()
>will only fail if it's passed invalid data, and we don't do that... so make
>it void and remove all the conditional code that deals with failure.
>
>The change also allows us to remove a few variables that were used for
>housekeeping between the signal handler and the main loop.
>---
> include/dixstruct.h |    6 ++----
> os/WaitFor.c        |   11 +++--------
> os/utils.c          |   28 +++-------------------------
> 3 files changed, 8 insertions(+), 37 deletions(-)
>
>diff --git a/include/dixstruct.h b/include/dixstruct.h
>index dd6347f..bed31dc 100644
>--- a/include/dixstruct.h
>+++ b/include/dixstruct.h
>@@ -150,11 +150,9 @@ extern long SmartScheduleTime;
> extern long SmartScheduleInterval;
> extern long SmartScheduleSlice;
> extern long SmartScheduleMaxSlice;
>-extern unsigned long SmartScheduleIdleCount;
> extern Bool SmartScheduleDisable;
>-extern Bool SmartScheduleIdle;
>-extern Bool SmartScheduleTimerStopped;
>-extern Bool SmartScheduleStartTimer(void);
>+extern void SmartScheduleStartTimer(void);
>+extern void SmartScheduleStopTimer(void);
> #define SMART_MAX_PRIORITY  (20)
> #define SMART_MIN_PRIORITY  (-20)
> 
>diff --git a/os/WaitFor.c b/os/WaitFor.c
>index ec1592c..7683477 100644
>--- a/os/WaitFor.c
>+++ b/os/WaitFor.c
>@@ -217,7 +217,8 @@ WaitForSomething(int *pClientsReady)
> 	XFD_COPYSET(&AllSockets, &LastSelectMask);
> #ifdef SMART_SCHEDULE
> 	}
>-	SmartScheduleIdle = TRUE;
>+	SmartScheduleStopTimer ();
>+
> #endif
> 	BlockHandler((pointer)&wt, (pointer)&LastSelectMask);
> 	if (NewOutputPending)
>@@ -237,13 +238,7 @@ WaitForSomething(int *pClientsReady)
> 	selecterr = GetErrno();
> 	WakeupHandler(i, (pointer)&LastSelectMask);
> #ifdef SMART_SCHEDULE
>-	if (i >= 0)
>-	{
>-	    SmartScheduleIdle = FALSE;
>-	    SmartScheduleIdleCount = 0;
>-	    if (SmartScheduleTimerStopped)
>-		(void) SmartScheduleStartTimer ();
>-	}
>+	SmartScheduleStartTimer ();
> #endif
> 	if (i <= 0) /* An error or timeout occurred */
> 	{
>diff --git a/os/utils.c b/os/utils.c
>index 31cb0af..6fc1f7d 100644
>--- a/os/utils.c
>+++ b/os/utils.c
>@@ -1513,10 +1513,6 @@ XNFstrdup(const char *s)
> 
> #ifdef SMART_SCHEDULE
> 
>-unsigned long	SmartScheduleIdleCount;
>-Bool		SmartScheduleIdle;
>-Bool		SmartScheduleTimerStopped;
>-
> #ifdef SIGVTALRM
> #define SMART_SCHEDULE_POSSIBLE
> #endif
>@@ -1526,7 +1522,7 @@ Bool		SmartScheduleTimerStopped;
> #define SMART_SCHEDULE_TIMER		ITIMER_REAL
> #endif
> 
>-static void
>+void
> SmartScheduleStopTimer (void)
> {
> #ifdef SMART_SCHEDULE_POSSIBLE
>@@ -1537,38 +1533,28 @@ SmartScheduleStopTimer (void)
>     timer.it_value.tv_sec = 0;
>     timer.it_value.tv_usec = 0;
>     (void) setitimer (ITIMER_REAL, &timer, 0);
>-    SmartScheduleTimerStopped = TRUE;
> #endif
> }
> 
>-Bool
>+void
> SmartScheduleStartTimer (void)
> {
> #ifdef SMART_SCHEDULE_POSSIBLE
>     struct itimerval	timer;
>     
>-    SmartScheduleTimerStopped = FALSE;
>     timer.it_interval.tv_sec = 0;
>     timer.it_interval.tv_usec = SmartScheduleInterval * 1000;
>     timer.it_value.tv_sec = 0;
>     timer.it_value.tv_usec = SmartScheduleInterval * 1000;
>-    return setitimer (ITIMER_REAL, &timer, 0) >= 0;
>+    setitimer (ITIMER_REAL, &timer, 0);
> #endif
>-    return FALSE;
> }
> 
> #ifdef SMART_SCHEDULE_POSSIBLE
> static void
> SmartScheduleTimer (int sig)
> {
>-    int olderrno = errno;
>-
>     SmartScheduleTime += SmartScheduleInterval;
>-    if (SmartScheduleIdle)
>-    {
>-	SmartScheduleStopTimer ();
>-    }
>-    errno = olderrno;
> }
> #endif
> 
>@@ -1592,14 +1578,6 @@ SmartScheduleInit (void)
> 	perror ("sigaction for smart scheduler");
> 	return FALSE;
>     }
>-    /* Set up the virtual timer */
>-    if (!SmartScheduleStartTimer ())
>-    {
>-	perror ("scheduling timer");
>-	return FALSE;
>-    }
>-    /* stop the timer and wait for WaitForSomething to start it */
>-    SmartScheduleStopTimer ();
>     return TRUE;
> #else
>     return FALSE;
>-- 
>1.5.3.4
>

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