Eric Lee / smarc-ti-linux-kernel

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Commit 40fcfc87222e2e8af6379ec366f0cb2a411570cd

Authored by Alan Cox
Committed by Linus Torvalds
1 parent d5abe66917
Exists in master and in 20 other branches dlt-processor-sdk-linux-03.00.00.04, newt-ti-linux-3.12.y, processor-sdk-linux-01.00.00, processor-sdk-linux-02.00.01, smarc-ti-linux-3.12.10, smarc-ti-linux-3.12.y, smarc-ti-linux-3.14.y, smarc-ti-linux-3.15.y, smarc-ti-lsk-linux-4.1.y, smarct3x-processor-sdk-04.01.00.06, smarct3x-processor-sdk-linux-02.00.01, smarct3x-processor-sdk-linux-03.00.00.04, smarct4x-800-processor-sdk-linux-02.00.01, smarct4x-processor-sdk-04.01.00.06, smarct4x-processor-sdk-linux-02.00.01, smarct4x-processor-sdk-linux-03.00.00.04, ti-linux-3.12.y, ti-linux-3.14.y, ti-linux-3.15.y, ti-lsk-linux-4.1.y

[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>

Showing 1 changed file with 15 additions and 5 deletions Side-by-side Diff

... ... @@ -7,7 +7,7 @@
7 7 default HZ_250
8 8 help
9 9 Allows the configuration of the timer frequency. It is customary
10   - to have the timer interrupt run at 1000 HZ but 100 HZ may be more
  10 + to have the timer interrupt run at 1000 Hz but 100 Hz may be more
11 11 beneficial for servers and NUMA systems that do not need to have
12 12 a fast response for user interaction and that may experience bus
13 13 contention and cacheline bounces as a result of timer interrupts.
14 14  
15 15  
16 16  
17 17  
... ... @@ -19,21 +19,30 @@
19 19 config HZ_100
20 20 bool "100 HZ"
21 21 help
22   - 100 HZ is a typical choice for servers, SMP and NUMA systems
  22 + 100 Hz is a typical choice for servers, SMP and NUMA systems
23 23 with lots of processors that may show reduced performance if
24 24 too many timer interrupts are occurring.
25 25  
26 26 config HZ_250
27 27 bool "250 HZ"
28 28 help
29   - 250 HZ is a good compromise choice allowing server performance
  29 + 250 Hz is a good compromise choice allowing server performance
30 30 while also showing good interactive responsiveness even
31   - on SMP and NUMA systems.
  31 + on SMP and NUMA systems. If you are going to be using NTSC video
  32 + or multimedia, selected 300Hz instead.
32 33  
  34 + config HZ_300
  35 + bool "300 HZ"
  36 + help
  37 + 300 Hz is a good compromise choice allowing server performance
  38 + while also showing good interactive responsiveness even
  39 + on SMP and NUMA systems and exactly dividing by both PAL and
  40 + NTSC frame rates for video and multimedia work.
  41 +
33 42 config HZ_1000
34 43 bool "1000 HZ"
35 44 help
36   - 1000 HZ is the preferred choice for desktop systems and other
  45 + 1000 Hz is the preferred choice for desktop systems and other
37 46 systems requiring fast interactive responses to events.
38 47  
39 48 endchoice
... ... @@ -42,5 +51,6 @@
42 51 int
43 52 default 100 if HZ_100
44 53 default 250 if HZ_250
  54 + default 300 if HZ_300
45 55 default 1000 if HZ_1000