Re: [Fwd: Re: [patch] Real-Time Preemption, -RT-2.6.9-mm1-V0.4]

[Lee Revell <rlrevell@joe-job.com>]

On Sat, 2004-10-30 at 23:13 +0200, Florian Schmidt wrote: 
> On Sat, 30 Oct 2004 16:26:35 -0400
> Lee Revell <rlrevell@joe-job.com> wrote:
> 
> > Take a look at the patch I posted to jackit-devel the other day to
> > calculate the CPU speed (previously we grabbed it from /proc/cpuinfo).
> > I just copied the code from realfeel2.
> > 
> 
> ah, ok.. tarball updated. The third argument is now a percentage. If the
> cycle count difference between two different wakeups differs more than the
> specified percentage from the "perfect" period, then a line is printed to
> the terminal showing by how much percent it differs. 
> 
> flo
> 

Here is a patch that causes the number of consecutive missed interrupts
to be printed, as well as setting RT priority itself instead of relying
on the rt_wakeup wrapper.

I have found that moving the mouse quickly will reliably cause many
interrupts to be missed.

Lee

--- wakeup/wakeup.cc	2004-10-30 17:11:08.000000000 -0400
+++ wakeup2/wakeup.cc	2004-10-30 21:03:21.000000000 -0400
@@ -90,6 +90,22 @@
 }
 // realfeel
 
+int set_realtime_priority(void)
+{
+	struct sched_param schp;
+	/*
+	 * set the process to realtime privs
+	 */
+	memset(&schp, 0, sizeof(schp));
+	schp.sched_priority = sched_get_priority_max(SCHED_FIFO);
+	
+	if (sched_setscheduler(0, SCHED_FIFO, &schp) != 0) {
+		perror("sched_setscheduler");
+		exit(1);
+	}
+
+	return 0;
+}
 
 
 
@@ -181,6 +197,8 @@
     perror("ioctl");
     exit(errno);
   }
+ 
+  set_realtime_priority();
   
   unsigned int irqs = 0;
   unsigned int missed_irqs = 0;
@@ -220,7 +238,7 @@
     irqs += data;
     // std::cout << data << std::endl;
     if (data > 1) {
-      std::cout << "ouch! we missed one ore more irq[s]" << std::endl;
+      std::cout << "ouch! we missed " << data << " or more irq[s]" << std::endl;
       missed_irqs++;
     }
   }

Lee