[patch, 2.6.9-rc4-mm1, 2.6.9-rc4] fix the prof=schedule feature

[Ingo Molnar]

* Andrew Morton <akpm@xxxxxxxx> wrote:

> > in the next mail i will send a patch against 2.6.9-rc4 too (which
> > luckily doesnt have the crash bug, but has the feature mismerge).
> 
> OK.  So it sounds like no additional patch will be needed for -mm?

the sched.c chunks below are still needed. prof=schedule must be driven
from schedule(), not from setscheduler().

The profile.c one is a cleanup. [ and you surely must be a great fan of
profiler cleanups by now B-) ]

the patch applies to 2.6.9-rc4 cleanly as well, and the sched.c bits are
necessary there too. I have tested this patch with and without
prof=schedule and it now produces the expected results:

   314 work_resched                              14.2727
   389 log_wait_commit                            1.2006
   391 kjournald                                  0.6872
   499 need_resched                               9.9800
  1549 worker_thread                              2.5310
  1649 wait_for_completion                        7.4615
  2551 do_exit                                    2.6435
  2999 schedule_timeout                          16.7542
  3073 io_schedule                               64.0208
  7863 preempt_schedule                         126.8226

the above is the scheduling profile of a bootup. ~40% of the reschedules
were caused by PREEMPT, ~20% by IO and the remaining ~40% by process
communication.

without this patch the output is a boring empty profile ...

	Ingo

Signed-off-by: Ingo Molnar <mingo@xxxxxxx>

--- linux/kernel/sched.c.orig
+++ linux/kernel/sched.c
@@ -2646,6 +2646,7 @@ asmlinkage void __sched schedule(void)
 			dump_stack();
 		}
 	}
+	profile_hit(SCHED_PROFILING, __builtin_return_address(0));
 
 need_resched:
 	preempt_disable();
@@ -3222,7 +3223,6 @@ static int setscheduler(pid_t pid, int p
 				policy != SCHED_NORMAL)
 			goto out_unlock;
 	}
-	profile_hit(SCHED_PROFILING, __builtin_return_address(0));
 
 	/*
 	 * Valid priorities for SCHED_FIFO and SCHED_RR are
--- linux/kernel/profile.c.orig
+++ linux/kernel/profile.c
@@ -22,14 +22,14 @@ static int __init profile_setup(char * s
 	int par;
 
 	if (!strncmp(str, "schedule", 8)) {
-		prof_on = 2;
+		prof_on = SCHED_PROFILING;
 		printk(KERN_INFO "kernel schedule profiling enabled\n");
 		if (str[7] == ',')
 			str += 8;
 	}
 	if (get_option(&str,&par)) {
 		prof_shift = par;
-		prof_on = 1;
+		prof_on = CPU_PROFILING;
 		printk(KERN_INFO "kernel profiling enabled (shift: %ld)\n",
 			prof_shift);
 	}

-
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