Path: csiph.com!aioe.org!bofh.it!news.nic.it!robomod From: Andi Kleen Newsgroups: linux.kernel Subject: Re: [PATCH RFC] x86, tsc: Allow for high latency in quick_pit_calibrate() Date: Wed, 03 Jun 2015 01:40:01 +0200 Message-ID: References: X-Original-To: Thomas Gleixner X-Extloop1: 1 X-Ironport-Av: E=Sophos;i="5.13,543,1427785200"; d="scan'208";a="719655796" MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.23 (2014-03-12) Sender: robomod@news.nic.it List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Approved: robomod@news.nic.it Lines: 24 Organization: linux.* mail to news gateway X-Original-Cc: Andy Lutomirski , Adrian Hunter , LKML , Linus Torvalds , X86 ML , "H. Peter Anvin" , Len Brown X-Original-Date: Tue, 2 Jun 2015 16:38:20 -0700 X-Original-Message-ID: <20150602233820.GP1187@tassilo.jf.intel.com> X-Original-References: <1432194944-29087-1-git-send-email-adrian.hunter@intel.com> <20150602194350.GN1187@tassilo.jf.intel.com> <20150602202037.GO1187@tassilo.jf.intel.com> X-Original-Sender: linux-kernel-owner@vger.kernel.org Xref: aioe.org linux.kernel:1156983 On Tue, Jun 02, 2015 at 11:03:26PM +0200, Thomas Gleixner wrote: > > > On Tue, 2 Jun 2015, Andi Kleen wrote: > > > > There's the code in tsc_msr.c. It should be relatively > > > straightforward to extend it to cover everything that intel_pstate > > > supports. > > > > That's a good idea, but we still need an always working fallback when the > > model number is not available. So Adrian's patch is needed in any > > case. > > Nonsense. The slow calibration is already a working fallback. Please read Adrian's description again. It's not working when the PIT read is too slow. That is when the new algorithm is needed. -Andi -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/