On Thu, 14 Jan 2021 at 07:25, 陳建宏 <reniuschengl@xxxxxxxxx> wrote: > > > Ulf Hansson <ulf.hansson@xxxxxxxxxx> 於 2021年1月13日 週三 下午6:53寫道： > > > > On Wed, 6 Jan 2021 at 10:27, Renius Chen <reniuschengl@xxxxxxxxx> wrote: > > > > > > The R/W performance of GL9763E is low with some platforms, which > > > support ASPM mechanism, due to entering L1 state very frequently > > > in R/W process. Enlarge its ASPM L1 entry delay to improve the > > > R/W performance of GL9763E. > > > > What do you mean by frequently? In between a burst of request or > > during a burst of request? > > GL9763E enters ASPM L1 state after a very short idle in default, even > during a burst of request. Okay, then it certainly makes sense to extend the idle period. Would you mind extending the commit message with some of this information, as I think it's useful. > > > I am thinking that this could have an effect on energy instead, but I > > guess it's not always straightforward to decide what's most important. > > > > Anyway, what does it mean when you change to use 0x3FF? Are you > > increasing the idle period? Then for how long? > > Yes, we considered that having high performance is more important than > saving power during a burst of request. > So we increased the idle period for 260us, by setting 0x3FF to the > ASPM L1 entry delay bits of our vendor-specific register. > Anyway, GL9763E can still enter ASPM L1 state by a longer idle. Most mmc controllers that uses runtime PM autosuspend for the same reasons, uses and idle period time of ~50us. 260us is in the same ballpark, so I am fine with that, if that works for you. However, can you please add a comment in the code (and preferably also to the commit message) that 0x3FF means using a 260us idle period? [...] Kind regards Uffe
