lkml.org 
[lkml]   [2002]   [Aug]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Subject[PATCH] per-arch load balancing
From
Date
Linus,

The attached patch implements (optional) per-architecture load balancing
so we can cleanly implement specialized load balancing behavior for
NUMA, hyperthreading, etc.

The new method is "arch_load_balance()" and is defined (if available) in
asm/smp_balance.h - otherwise it defines away. Currently, we call it
from "find_busiest_queue()".

This patch, against current BK, only implements the infrastructure and
not any particular new logic. This is a similar implementation as found
in 2.4-ac.

Please, apply.

Robert Love

diff -urN linux-2.5.31/include/linux/smp_balance.h linux/include/linux/smp_balance.h
--- linux-2.5.31/include/linux/smp_balance.h Wed Dec 31 19:00:00 1969
+++ linux/include/linux/smp_balance.h Sat Aug 24 22:10:00 2002
@@ -0,0 +1,14 @@
+#ifndef _LINUX_SMP_BALANCE_H
+#define _LINUX_SMP_BALANCE_H
+
+/*
+ * per-architecture load balancing logic, e.g. for hyperthreading
+ */
+
+#ifdef ARCH_HAS_SMP_BALANCE
+#include <asm/smp_balance.h>
+#else
+#define arch_load_balance(x, y) (0)
+#endif
+
+#endif /* _LINUX_SMP_BALANCE_H */
diff -urN linux-2.5.31/kernel/sched.c linux/kernel/sched.c
--- linux-2.5.31/kernel/sched.c Sat Aug 10 21:41:24 2002
+++ linux/kernel/sched.c Sat Aug 24 22:10:00 2002
@@ -630,6 +630,8 @@
return nr_running;
}

+#include <linux/smp_balance.h>
+
/*
* find_busiest_queue - find the busiest runqueue.
*/
@@ -639,6 +641,12 @@
runqueue_t *busiest, *rq_src;

/*
+ * Handle architecture-specific balancing, such as hyperthreading.
+ */
+ if (arch_load_balance(this_cpu, idle))
+ return NULL;
+
+ /*
* We search all runqueues to find the most busy one.
* We do this lockless to reduce cache-bouncing overhead,
* we re-check the 'best' source CPU later on again, with


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:28    [W:0.063 / U:0.552 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site