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author | Vincent Guittot <vincent.guittot@linaro.org> | 2018-07-11 10:34:46 +0200 |
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committer | Wei Xu <xuwei5@hisilicon.com> | 2018-07-17 12:19:25 +0100 |
commit | a5956defe5a537447a83de9b4bcd6a7c9aa1cc74 (patch) | |
tree | 62a24d08511b044107c9645ff45c3396cc509ff8 /arch/arm64/boot/dts/hisilicon/hi6220.dtsi | |
parent | 8883ac1db3e284e9ad48ddad37f5eb3c2730510d (diff) |
arm64: hikey960: update idle-states
Update entry/exit latency and residency time of hikey960 to use more
realistic figures based on unitary tests done on the platform.
The complete results (in us) :
big cluster
cluster CPU
max entry latency 800 400
max exit latency 2900 550
residency 903Mhz 5000 1500
residency 2363Mhz 0 1500
little cluster
cluster CPU
max entry latency 500 400
max exit latency 1600 650
residency 533Mhz 8000 4500
residency 1844Mhz 0 1500
We can see that the residency time depends of the running OPP which is not
handled for now. Then we also have to take into account the constraint of
a residency time shorter than the tick to get full advantage of idle loop
reordering(tick is stopped if idle duration is higher than tick period).
Finally the selected residency value are :
big cluster
cluster CPU
residency 3700 1500
little cluster
cluster CPU
residency 3500 1500
A simple test with a task waking up every 11.111ms shows improvement:
- 5% a lowest OPP
- 22% at highest OPP
The period has been chosen:
- to be shorter than old cluster residency time and longer than new
residency time of cluster off C-state
- to prevent any sync with tick (4ms) when running tests that can add
some variances between tests
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Leo Yan <leo.yan@linaro.org>
Signed-off-by: Wei Xu <xuwei5@hisilicon.com>
Diffstat (limited to 'arch/arm64/boot/dts/hisilicon/hi6220.dtsi')
0 files changed, 0 insertions, 0 deletions