> From: lihuisong (C) [mailto:lihuis...@huawei.com] > Sent: Tuesday, 26 March 2024 03.12 > > 在 2024/3/22 20:35, Morten Brørup 写道: > >> From: lihuisong (C) [mailto:lihuis...@huawei.com] > >> Sent: Friday, 22 March 2024 09.54
[...] > >> For the case need PM QoS in DPDK, I think, it is better to set cpu > >> latency to zero to prevent service thread from the deeper the idle > state. > > It would defeat the purpose (i.e. not saving sufficient amounts of > power) if the CPU cannot enter a deeper idle state. > Yes, it is not good for power. > AFAIS, PM QoS is just to decrease the influence for performance. > Anyway, if we set to zero, system can be into Cstates-0 at least. > > > > Personally, I would think a wake-up latency of up to 10 microseconds > should be fine for must purposes. > > Default Linux timerslack is 50 microseconds, so you could also use > that value. > How much CPU latency is ok. Maybe, we can give the decision to the > application. Yes, the application should decide the acceptable worst-case latency. > Linux will collect all these QoS request and use the minimum latency. > what do you think, Morten? For the example application, you could use a value of 50 microseconds and refer to this value also being the default timerslack in Linux.
