From: Adrian Bunk <bunk@stusta.de>
Date: Thu, 7 Dec 2006 01:14:19 +0000 (+0100)
Subject: [PATCH] i386: Clean up smp_tune_scheduling()
X-Git-Tag: v2.6.20-rc1~145^2^2~8^2~1
X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=d9408cefe677636bc1c100fdcfac0b2ab9ff87bf;p=linux-2.6-omap-h63xx.git

[PATCH] i386: Clean up smp_tune_scheduling()

- remove the write-only local variable "bandwidth"
- don't set "max_cache_size" in the (cachesize < 0) case:
  that's already handled in kernel/sched.c:measure_migration_cost()

Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andi Kleen <ak@suse.de>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---

diff --git a/arch/i386/kernel/smpboot.c b/arch/i386/kernel/smpboot.c
index 346f27f4c79..b4e6f32de45 100644
--- a/arch/i386/kernel/smpboot.c
+++ b/arch/i386/kernel/smpboot.c
@@ -1130,34 +1130,15 @@ exit:
 }
 #endif
 
-static void smp_tune_scheduling (void)
+static void smp_tune_scheduling(void)
 {
 	unsigned long cachesize;       /* kB   */
-	unsigned long bandwidth = 350; /* MB/s */
-	/*
-	 * Rough estimation for SMP scheduling, this is the number of
-	 * cycles it takes for a fully memory-limited process to flush
-	 * the SMP-local cache.
-	 *
-	 * (For a P5 this pretty much means we will choose another idle
-	 *  CPU almost always at wakeup time (this is due to the small
-	 *  L1 cache), on PIIs it's around 50-100 usecs, depending on
-	 *  the cache size)
-	 */
 
-	if (!cpu_khz) {
-		/*
-		 * this basically disables processor-affinity
-		 * scheduling on SMP without a TSC.
-		 */
-		return;
-	} else {
+	if (cpu_khz) {
 		cachesize = boot_cpu_data.x86_cache_size;
-		if (cachesize == -1) {
-			cachesize = 16; /* Pentiums, 2x8kB cache */
-			bandwidth = 100;
-		}
-		max_cache_size = cachesize * 1024;
+
+		if (cachesize > 0)
+			max_cache_size = cachesize * 1024;
 	}
 }