From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nishanth Aravamudan Date: Tue, 05 Aug 2008 17:34:47 +0000 Subject: Re: [BISECTION RESULT] sched: revert cpu_clock to Message-Id: <20080805173447.GD7812@us.ibm.com> List-Id: References: <20080804194646.GA17390@us.ibm.com> <1217926585.3589.113.camel@twins> In-Reply-To: <1217926585.3589.113.camel@twins> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Peter Zijlstra Cc: mingo@elte.hu, tony.luck@intel.com, linux-ia64@vger.kernel.org, LKML , Bill Gatliff , Russell King - ARM Linux On 05.08.2008 [10:56:25 +0200], Peter Zijlstra wrote: > On Mon, 2008-08-04 at 12:46 -0700, Nishanth Aravamudan wrote: > > Bisection on an x455 (2-node IA64) showed that commit > > 27ec4407790d075c325e1f4da0a19c56953cce23 (sched: make cpu_clock() > > globally synchronous) broke booting. I see the uncompressing initramfs > > message and then nothing on the console. I wait about 5 minutes (which > > is way longer than it takes for the first console messages to get > > printed normally). The commit immediately before it works fine. > > > > The commit no longer cleanly reverts, but I tried to manually put things > > back to the way they were before in cpu_clock(). The resulting kernel > > boots fine. I could figure out a clean way to leave cpu_clock() in > > sched_clock.c because of all the rq dependencies from sched.c. The > > attempt I tested is below [1]. This patch is *NOT* for inclusion, just > > to demonstrate what I tested. > > > > I'm happy to test any better patches. > > Does this work for you? > > --- > Subject: sched_clock: delay using sched_clock() > > Some arch's can't handle sched_clock() being called too early - delay > this until sched_clock_init() has been called. > > Reported-by: Bill Gatliff > Signed-off-by: Peter Zijlstra > CC: Russell King - ARM Linux Yep, this fixes things on the box, as well. Tested-by: Nishanth Aravamudan Thanks, Nish -- Nishanth Aravamudan IBM Linux Technology Center