> -----Original Message----- > From: devel@edk2.groups.io [mailto:devel@edk2.groups.io] On Behalf Of Brian > J. Johnson > Sent: Tuesday, March 24, 2020 12:39 AM > To: devel@edk2.groups.io; Ni, Ray; Laszlo Ersek; Wu, Hao A; > r...@edk2.groups.io > Cc: Dong, Eric; Kinney, Michael D; Zeng, Star > Subject: Re: [edk2-devel] [RFC][PATCH v1] UefiCpuPkg/MpInitLib DXE: Reduce > AP status check interval > > On 3/23/20 9:37 AM, Ni, Ray wrote: > >>> Laszlo, > >>> Adding a PCD means platform integrators need to consider which value to > set. > >>> Most of the time, they may just use the default PCD value. > >>> Then, why not we add the PCD later when a real case is met? > >> > >> The patch changes existent behavior; it is not for a newly introduced > >> feature. > >> > >> Because most platforms are not in the edk2 tree, we don't know what > >> platforms could be regressed by increasing the polling frequency > >> tenfold. (And remember that the polling action has O(n) cost, where "n" > >> is the logical processor count.) > >> > >> Under your suggestion, the expression "real case is met" amounts to > >> "someone reports a regression" (possibly after the next stable tag, > >> even). I don't think that's a good idea. > >> In particular, the patch is motivated by RegisterCpuFeaturesLib -- the > >> CpuFeaturesInitialize() function -- on some platform(s) that Hao uses. > >> But there are platforms that don't use RegisterCpuFeaturesLib, and still > >> use MpInitLib. > > > > OK. I agree with your suggestion. > > Thank you. I agree with Laszlo: MP initialization is tricky to scale, > and platform dependent. My group builds real machines with thousands of > APs, and we have had to do various tweaks to the MP init. code. Having > a PCD to adjust this timeout will be very useful.
Thanks all for the feedbacks. Please grant me some time to prepare a new version of the patch. Best Regards, Hao Wu > > Thanks, > -- > Brian J. Johnson > Enterprise X86 Lab > > Hewlett Packard Enterprise > brian.john...@hpe.com > > > -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#56121): https://edk2.groups.io/g/devel/message/56121 Mute This Topic: https://groups.io/mt/71925352/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
