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| author | Ingo Molnar <mingo@elte.hu> | 2006-02-17 13:52:44 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-02-17 13:59:26 -0800 |
| commit | 4bbf39c29bc3409d6454faf0dfa1b3b0aa2ac2af (patch) | |
| tree | 2f8ed8aa42a1645a9cb3306ce93c9e4b63536630 /arch/s390/Kconfig | |
| parent | 05efc67d100ff6c3364604b72729addf1a86fdab (diff) | |
| download | lwn-4bbf39c29bc3409d6454faf0dfa1b3b0aa2ac2af.tar.gz lwn-4bbf39c29bc3409d6454faf0dfa1b3b0aa2ac2af.zip | |
[PATCH] Introduce CONFIG_DEFAULT_MIGRATION_COST
Heiko Carstens <heiko.carstens@de.ibm.com> wrote:
The boot sequence on s390 sometimes takes ages and we spend a very long
time (up to one or two minutes) in calibrate_migration_costs. The time
spent there differs from boot to boot. Also the calculated costs differ
a lot. I've seen differences by up to a factor of 15 (yes, factor not
percent). Also I doubt that making these measurements make much sense on
a completely virtualized architecture where you cannot tell how much cpu
time you will get anyway.
So introduce the CONFIG_DEFAULT_MIGRATION_COST method for an architecture
to set the scheduler migration costs. This turns off automatic detection
of migration costs. Makes sense on virtual platforms, where migration
costs are hard to measure accurately.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/s390/Kconfig')
| -rw-r--r-- | arch/s390/Kconfig | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index b66602ad7b33..b7ca5bf9acfc 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -80,6 +80,10 @@ config HOTPLUG_CPU can be controlled through /sys/devices/system/cpu/cpu#. Say N if you want to disable CPU hotplug. +config DEFAULT_MIGRATION_COST + int + default "1000000" + config MATHEMU bool "IEEE FPU emulation" depends on MARCH_G5 |