Messages in this thread | | | Subject | Re: [RFC PATCH 0/2] PM / devfreq: Add delayed timer for polling | From | Lukasz Luba <> | Date | Mon, 13 Jul 2020 09:55:24 +0100 |
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Hi Willy
On 7/10/20 4:12 PM, Willy Wolff wrote: > Hi Lukasz, > > On 2020-07-08-15-25-03, Lukasz Luba wrote: >> Hi Willy, >> >> On 7/3/20 1:33 PM, Willy Wolff wrote: >>> Hi Chanwoo, >>> >>> I think it doesn't help on the benchmark I suggested that is doing only memory >>> accesses. With both timer, I have the same timing. >>> >>> To test the benchmark with these new patches about timer: >>> >>> git clone https://github.com/wwilly/benchmark.git \ >>> && cd benchmark \ >>> && source env.sh \ >>> && ./bench_build.sh \ >>> && bash source/scripts/test_dvfs_mem_patched.sh >>> >>> The benchmark is set by default to run for 1s, but you can increase this by >>> tweaking the script as: >>> >>> taskset 8 ./bench_install/bin/microbe_cache 33554431 0 9722222 <TIME in sec> ${little_freq} >>> >>> >>> Also, as I reported the issue, would it be possible to add a >>> Reported-by: Willy Wolff <willy.mh.wolff.ml@gmail.com> ? >>> Many thanks in advance. >> >> Thank you for your good work and the benchmark. I hope you will continue >> to use it and report some issues. I am going to send a follow up patches >> for the DMC and I will add your 'Reported-by'. In the tests I can see >> the improvements, but it's worth to consult with you if I understand >> the new results correctly. >> > > Thanks for that. I will follow on the other patch thread discussion. > >> I think there is still some area for improvements in the devfreq and you >> could find the interesting bits to contribute. > > In fact, this benchmark is motivated about part of my PhD research that has just > been accepted at LCTES2020: "Performance Optimization on big.LITTLE Architectures: > A Memory-latency Aware Approach" at https://dl.acm.org/doi/10.1145/3372799.3394370 >
Congrats and thank you for the link (I will read it).
> Basically, it's about snooping latency with "bad" CPU DVFS choice on big.LITTLE > systems or more generally SMP/AMP architecture. I'm cleaning up my code and will > propose patches as an RFC later. It introduces a new CPU DVFS governor to limit > snooping latency.
This is interesting, please add me on CC in the patch set.
Regards, Lukasz
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