Increasing CONFIG_HZ on Arch ARM kernels

[soundcheck]

Hi there.

I just ran linpack on my RPI. Not sure though if linpack is giving reliable respectively relevant data:

$this->bbcode_second_pass_code('', '
* RaspberryPi B+
* silghtly overclocked
arm_freq=900
core_freq=480
sdram_freq=560
gpu_freq=250
over_voltage=2
avoid_pwm_pll=1
force_turbo=1
gpu_mem_512=16
* performance governor
* headless operation
* Cases: 100Hz and 300Hz
* Linux 3.16.3-1-ARCH #1 PREEMPT Mon Sep 22 03:53:26 MDT 2014 armv6l GNU/Linux
* Linpack Benchmark

#########################################################
Reps Time(s) DGEFA DGESL OVERHEAD KFLOPS
----------------------------------------------------
32 0.87 88.22% 3.04% 8.74% 55375.088
64 1.74 88.23% 3.03% 8.74% 55357.371
128 3.48 88.24% 3.03% 8.73% 55354.948
256 6.96 88.23% 3.04% 8.73% 55353.222
512 13.92 88.24% 3.04% 8.73% 55354.586

#########################################################
Reps Time(s) DGEFA DGESL OVERHEAD KFLOPS
----------------------------------------------------
32 0.82 87.76% 3.07% 9.17% 58690.948
64 1.65 87.83% 3.08% 9.09% 58629.795
128 3.30 87.88% 3.11% 9.01% 58581.281
256 6.60 87.85% 3.11% 9.04% 58594.520
512 13.19 87.88% 3.10% 9.02% 58588.818
######################################################### 6%+
')

Please let me know if there are better benchmarks to compare the different scenarios.

Cheers

[soundcheck]

Hi there.

I played around with the settings a little more.


I had the feeling that my latest settings - 300Hz and DynticksOff - were causing slight hickups. (While streaming music I noticed a dropout once in a while (>30s) - different then the typical XRUNS)

Things got stable again at 250Hz. And DynticksOn (default) .


I think 250Hz and DynticksOn would be a good choice for the RPI. Linpack gave me around 58000Kflops.
Basically a rather logical confirmation that the timer has a certain impact on the performance.
300Hz runs stable on my Cubitruck. Which also makes sense considering it's higher CPU frequency and 3 times higher throughput.


One thing I realized. During the benchmarks I had close to no other apps running. When starting up my streaming app deamon (squeezelite) in the background and having it idling around there. Linpack dropped to around 46000Klfops. Not sure if this is a typical behaviour. I don't have much experience with linpack. I'll have a closer look at that.

Cheers