Re: [dev] [st] Limit refresh rate

From: Mihail Zenkov <>
Date: Fri, 15 Feb 2013 22:13:13 +0000

2013/2/15, Christoph Lohmann <>:
> Please try to see how much the CPU usage changed with the defaults in
> the repository. I canít really apply 5 fps; this makes output feel like
> the terminal is hanging.

I try measure on hd6770 with open source driver - it have problem with
2d acceleration (after jump to KMS), but it make difference more clear
(I suppose arm hardware have mostly same performance). First, with
xfps=60 it have somting like overflow: it freeze st output to 100-300
ms each 2-3 sec (on active updating).

Second, I measure CPU usage on real task - search in mc:
default xfps=60 actionfps=30
mc 68.5% X 26% st 3.4%

xfps=30 actionfps=15
mc 76.9% X 15,7% st 4%

xfps=30 actionfps=10
mc 80.9% X 11,8% st 4,2%

xfps=30 actionfps=5
mc 84,8% X 7,5% st 4,2%

Some comment on result: mc - better when it bigger (as it main task),
X and st - better lower. I have 3-core cpu. With single core cpu
result will by match worse as X and st cpu usage detain main task

I agree, that 5fps should not be by default. But I don't see
difference when xfps > 30. Maybe xfps=30 actionfps=15 good enough as

In any case, as you move it config.h any one can set it as wish.
Received on Fri Feb 15 2013 - 23:13:13 CET

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