From mboxrd@z Thu Jan 1 00:00:00 1970 From: Richard Cochran Subject: Re: [PATCH v4 1/4] Produce system time from correlated clocksource Date: Tue, 20 Oct 2015 21:36:39 +0200 Message-ID: <20151020193639.GA15095@localhost.localdomain> References: <20151020085408.GA2542@netboy> <20151020115113.GA23428@netboy> <20151020145523.GA5207@netboy> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: John Stultz , Christopher Hall , Jeff Kirsher , "H. Peter Anvin" , Ingo Molnar , Peter Zijlstra , "x86@kernel.org" , intel-wired-lan@lists.osuosl.org, netdev@vger.kernel.org, lkml , kevin.b.stanton@intel.com To: Thomas Gleixner Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Tue, Oct 20, 2015 at 09:11:21PM +0200, Thomas Gleixner wrote: > Darn, we don't want to have that kind of sampling in every driver > which has this kind of problem even if it looks like the simpler > choice for this particular use case. This is going to be something > which next generation chips will have on more than just the audio > interface and we realy want to have a generic solution for this. Right, having multiple drivers sampling is bad. Just thinking out loud: how about a service layer that can handle multiple drivers? The layer samples at the maximum requested rate, and buffers the history for the maximum requested backlog. The non-max rate users simply get a higher resolution than they need. A generic solution would handle any history length for old time stamps, within reason. I think hard coding 4 ms (or 8 ms or 800 ms) is clunky. Thanks, Richard