From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753296AbcJEIVN (ORCPT ); Wed, 5 Oct 2016 04:21:13 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:38369 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751230AbcJEIVM (ORCPT ); Wed, 5 Oct 2016 04:21:12 -0400 Date: Wed, 5 Oct 2016 10:21:02 +0200 From: Sebastian Andrzej Siewior To: Peter Zijlstra Cc: mingo@kernel.org, tglx@linutronix.de, juri.lelli@arm.com, rostedt@goodmis.org, xlpang@redhat.com, linux-kernel@vger.kernel.org, mathieu.desnoyers@efficios.com, jdesfossez@efficios.com, bristot@redhat.com Subject: Re: [RFC][PATCH 4/4] futex: Rewrite FUTEX_UNLOCK_PI Message-ID: <20161005082102.lm3jze3hzikkzxcg@linutronix.de> References: <20161003091234.879763059@infradead.org> <20161003091847.704255067@infradead.org> <20161005074147.qws2fx2n3o56y2r4@linutronix.de> <20161005080912.GF3142@twins.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20161005080912.GF3142@twins.programming.kicks-ass.net> User-Agent: NeoMutt/20160916 (1.7.0) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2016-10-05 10:09:12 [+0200], Peter Zijlstra wrote: > On Wed, Oct 05, 2016 at 09:41:47AM +0200, Sebastian Andrzej Siewior wrote: > > are those problems DL related? > > One of them, the other is that PI thing you did that ugly nodeboost > thing for, right? this no-de-boost yes. This is probably a problem since we have this "delayed" wake-up. I've been thinking about a marked in PI state to ignore a de-boost so the spin_unlock() won't be a problem. But if I understand it right, then this won't solve the DL problem since you can't have two tasks at the same priority. Sebastian