From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rich Felker Date: Tue, 04 Oct 2016 20:58:37 +0000 Subject: Re: [PATCH v7 2/2] clocksource: add J-Core timer/clocksource driver Message-Id: <20161004205837.GC19318@brightrain.aerifal.cx> List-Id: References: <22c1ee0f908fe3bf8b70f5e87d659ceb29af1434.1474693319.git.dalias@libc.org> <20160926210716.GA12855@brightrain.aerifal.cx> <4b02ba7d-4a31-297a-bbbd-be26da615e7b@linaro.org> <20161003221039.GR19318@brightrain.aerifal.cx> <20161004070623.GM14933@linux.vnet.ibm.com> In-Reply-To: <20161004070623.GM14933-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: "Paul E. McKenney" Cc: Daniel Lezcano , devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-sh-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Rob Herring , Mark Rutland , Thomas Gleixner On Tue, Oct 04, 2016 at 12:06:23AM -0700, Paul E. McKenney wrote: > On Mon, Oct 03, 2016 at 06:10:39PM -0400, Rich Felker wrote: > > On Mon, Sep 26, 2016 at 11:27:14PM +0200, Daniel Lezcano wrote: > > > On 26/09/2016 23:07, Rich Felker wrote: > > > > Ping. Is there anything that still needs to be changed for this driver > > > > to be acceptable? > > > > > > It is on my radar. I'm reviewing it. > > > > > > Can you elaborate the workaround mentioned in the changelog. I have been > > > digging into the lkml@ thread but it is not clear if the issue is > > > related to the time framework, the driver itself or whatever else. Can > > > you clarify that ? > > > > Do you have comments on any remaining issues other than this > > workaround? If not I don't mind removing the workaround and trying to > > solve the issue separately later. Let me know and either way I'll > > submit a v8. > > One question of interest to me is whether this patchset prevents the > RCU CPU stall warnings that you are seeing. With the 5ms minimum delta, I didn't observe any rcu_sched stall warnings. At 2.5ms I thought it was gone but eventually saw one. With the previous mindelta = 1, i.e. 1 hardware bus period, I get the stalls regularly. Rich