Re: HZ, preferably as small as possible

From: Thunder from the hill (thunder@ngforever.de)
Date: Wed Jul 10 2002 - 17:41:23 EST

Hi,

On Wed, 10 Jul 2002, Thunder from the hill wrote:
> Want a config option? Either int or bool (CONFIG_LOW_HZ). It's not too
> much effort.

I guess I forgot the half of it...

What arches do we want?

Index: arch/i386/Config.help
===================================================================
RCS file: /var/cvs/thunder-2.5/arch/i386/Config.help,v
retrieving revision 1.4
diff -p -u -r1.4 Config.help
--- arch/i386/Config.help 7 Jul 2002 09:59:46 -0000 1.4
+++ arch/i386/Config.help 10 Jul 2002 22:40:17 -0000
@@ -991,3 +991,13 @@ CONFIG_X86_EARLY_PRINTK
   to the console much earlier in the boot process than printk. This
   is useful when debugging fatal problems early in the boot sequence
   (e.g. within setup_arch). If unsure, say N.
+
+Low kernel scheduler rate
+CONFIG_SCHED_LOW_HZ
+ Enable this if you care about your CPU sleeping time. The current
+ interval for scheduling processes in the kernel has recently been
+ increased. The advantage is less latency for many things that depend
+ on the timer, the disadvantage is that your cpu will probably not
+ go to sleep in time (so CPU power management will possibly not work
+ at all)
+
Index: include/asm-i386/param.h
===================================================================
RCS file: /var/cvs/thunder-2.5/include/asm-i386/param.h,v
retrieving revision 1.2
diff -p -u -r1.2 param.h
--- include/asm-i386/param.h 6 Jul 2002 18:17:30 -0000 1.2
+++ include/asm-i386/param.h 10 Jul 2002 22:40:17 -0000
@@ -2,7 +2,11 @@
 #define _ASMi386_PARAM_H
 
 #ifdef __KERNEL__
-# define HZ 1000 /* Internal kernel timer frequency */
+# ifdef CONFIG_SCHED_LOW_HZ
+# define HZ 100 /* Internal kernel timer frequency */
+# else
+# define HZ 1000 /* Internal kernel timer frequency */
+# endif
 # define USER_HZ 100 /* .. some user interfaces are in "ticks" */
 # define CLOCKS_PER_SEC (USER_HZ) /* like times() */
 #endif

                                                        Regards,
                                                        Thunder 

-- 
(Use http://www.ebb.org/ungeek if you can't decode)
------BEGIN GEEK CODE BLOCK------
Version: 3.12
GCS/E/G/S/AT d- s++:-- a? C++$ ULAVHI++++$ P++$ L++++(+++++)$ E W-$
N--- o?  K? w-- O- M V$ PS+ PE- Y- PGP+ t+ 5+ X+ R- !tv b++ DI? !D G
e++++ h* r--- y- 
------END GEEK CODE BLOCK------

-
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/

This archive was generated by hypermail 2b29 : Mon Jul 15 2002 - 22:00:18 EST