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[PATCH] HZ: 300Hz support 

Fix two things.  Firstly the unit is "Hz" not "HZ".  Secondly it is useful
to have 300Hz support when doing multimedia work.  250 is fine for us in
Europe but the US frame rate is 30fps (29.99 blah for pedants).  300 gives
us a tick divisible by both 25 and 30, and for interlace work 50 and 60.
It's also giving similar performance to 250Hz.

I'd argue we should remove 250 and add 300, but that might be excess
disruption for now.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Alan Cox 2006-12-06 20:37:27 -08:00 committed by Linus Torvalds
parent d5abe66917
commit 40fcfc8722
1 changed files with 15 additions and 5 deletions
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20
kernel/Kconfig.hz
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@ -7,7 +7,7 @@ choice
default HZ_250
help
Allows the configuration of the timer frequency. It is customary
to have the timer interrupt run at 1000 HZ but 100 HZ may be more
to have the timer interrupt run at 1000 Hz but 100 Hz may be more
beneficial for servers and NUMA systems that do not need to have
a fast response for user interaction and that may experience bus
contention and cacheline bounces as a result of timer interrupts.
@ -19,21 +19,30 @@ choice
config HZ_100
bool "100 HZ"
help
100 HZ is a typical choice for servers, SMP and NUMA systems
100 Hz is a typical choice for servers, SMP and NUMA systems
with lots of processors that may show reduced performance if
too many timer interrupts are occurring.
config HZ_250
bool "250 HZ"
help
250 HZ is a good compromise choice allowing server performance
250 Hz is a good compromise choice allowing server performance
while also showing good interactive responsiveness even
on SMP and NUMA systems.
on SMP and NUMA systems. If you are going to be using NTSC video
or multimedia, selected 300Hz instead.
config HZ_300
bool "300 HZ"
help
300 Hz is a good compromise choice allowing server performance
while also showing good interactive responsiveness even
on SMP and NUMA systems and exactly dividing by both PAL and
NTSC frame rates for video and multimedia work.
config HZ_1000
bool "1000 HZ"
help
1000 HZ is the preferred choice for desktop systems and other
1000 Hz is the preferred choice for desktop systems and other
systems requiring fast interactive responses to events.
endchoice
@ -42,5 +51,6 @@ config HZ
int
default 100 if HZ_100
default 250 if HZ_250
default 300 if HZ_300
default 1000 if HZ_1000