From mboxrd@z Thu Jan 1 00:00:00 1970 From: Aravind Gopalakrishnan Subject: Re: [PATCH 0/1] speeding up cpu_up() Date: Fri, 1 May 2015 19:42:52 -0500 Message-ID: <55441D8C.2080509@amd.com> References: <1429404795-23260-1-git-send-email-lenb@kernel.org> <20150420071556.GB14315@gmail.com> <20150501224729.GN10239@pd.tnic> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20150501224729.GN10239@pd.tnic> Sender: linux-kernel-owner@vger.kernel.org To: Borislav Petkov , Len Brown Cc: Ingo Molnar , X86 ML , Linux PM list , "linux-kernel@vger.kernel.org" , Thomas Gleixner , "H. Peter Anvin" List-Id: linux-pm@vger.kernel.org On 5/1/15 5:47 PM, Borislav Petkov wrote: > On Fri, May 01, 2015 at 02:42:39PM -0700, Len Brown wrote: >> On Mon, Apr 20, 2015 at 12:15 AM, Ingo Molnar wrote: >> >>> So instead of playing games with an ancient delay, I'd suggest we >>> install the 10 msec INIT assertion wait as a platform quirk instead, >>> and activate it for all CPUs/systems that we think might need it, with >>> a sufficiently robust and future-proof quirk cutoff condition. >>> >>> New systems won't have the quirk active and thus won't have to have >>> this delay configurable either. >> Okay, at this time, I think the quirk would apply to: >> >> 1. Intel family 5 (original pentium) -- some may actually need the quirk >> 2. Intel family F (pentium4) -- mostly b/c I don't want to bother >> finding/testing p4 >> 3. All AMD (happy to narrow down, if somebody can speak for AMD) > Aravind and I could probably test on a couple of AMD boxes to narrow down. > > @Aravind, see here: > > https://lkml.kernel.org/r/87d69aab88c14d65ae1e7be55050d1b689b59b4b.1429402494.git.len.brown@intel.com > > You could ask around whether a timeout is needed between the assertion > and deassertion of INIT done by the BSP when booting other cores. Sure, I'll ask around and try mdelay(0) on some systems as well. I can gather Fam15h, Fam16h but don't have K8's or older. Will let you know how it goes. -Aravind. > If not, we probably should convert, at least modern AMD machines, to the > no-delay default. >