From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ingo Molnar Subject: Re: [PATCH 0/1] speeding up cpu_up() Date: Mon, 20 Apr 2015 09:15:56 +0200 Message-ID: <20150420071556.GB14315@gmail.com> References: <1429404795-23260-1-git-send-email-lenb@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1429404795-23260-1-git-send-email-lenb@kernel.org> Sender: linux-kernel-owner@vger.kernel.org To: Len Brown Cc: x86@kernel.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, Borislav Petkov , Thomas Gleixner , "H. Peter Anvin" List-Id: linux-pm@vger.kernel.org * Len Brown wrote: > The following patch... > > [PATCH 1/1] x86: replace cpu_up hard-coded mdelay with variable > > enables reducing cpu_up() time by 10ms on modern systems. > > This means that for every processor in the system, > boot-time and resume-time can be reduced by 10ms per-processor. > > Once this patch is accepted, I'll send a subsequent patch > to update the default delay, as appropriate. > > thanks, > Len Brown, Intel Open Source Technology Center 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. Thanks, Ingo