From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:57608) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VTXlZ-0002zg-7Z for qemu-devel@nongnu.org; Tue, 08 Oct 2013 09:56:07 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VTXlT-0002xE-7s for qemu-devel@nongnu.org; Tue, 08 Oct 2013 09:56:01 -0400 Received: from mx1.redhat.com ([209.132.183.28]:31087) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VTXlS-0002x8-Uq for qemu-devel@nongnu.org; Tue, 08 Oct 2013 09:55:55 -0400 Message-ID: <52540EDE.6040701@redhat.com> Date: Tue, 08 Oct 2013 15:55:42 +0200 From: Paolo Bonzini MIME-Version: 1.0 References: <1381222058-16701-1-git-send-email-pbonzini@redhat.com> <52540CEF.2030507@suse.de> In-Reply-To: <52540CEF.2030507@suse.de> Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH 0/8] Make icount thread-safe List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: =?ISO-8859-15?Q?Andreas_F=E4rber?= Cc: qemu-devel@nongnu.org, alex@alex.org.uk Il 08/10/2013 15:47, Andreas F=E4rber ha scritto: > Am 08.10.2013 10:47, schrieb Paolo Bonzini: >> This series moves the icount state under the same seqlock as the "norm= al" >> vm_clock implementation. >> >> It is not yet 100% thread-safe, because the CPU list should be moved >> under RCU protection (due to the call to !all_cpu_threads_idle() >> in qemu_clock_warp). However it is a substantial step forward, the >> only uncovered case being CPU hotplug. >> >> Please review. >> >> Paolo >> >> Paolo Bonzini (8): >> timers: extract timer_mod_ns_locked and timerlist_rearm >> timers: add timer_mod_anticipate and timer_mod_anticipate_ns >=20 >> timers: use cpu_get_icount() directly >> timers: reorganize icount_warp_rt >> timers: prepare the code for future races in calling qemu_clock_warp >> timers: introduce cpu_get_clock_locked >> timers: document (future) locking rules for icount >> timers: make icount thread-safe >=20 > These patches touch cpus.c exclusively, so "timers:" is rather misleadi= ng. I can change that to "icount". > As you know I have pending patches (in need of rebase due to the > performance issue you raised) moving the icount CPU fields around. > Is there anything in particular I should be aware of? Looks to me as if > this may be orthogonal? It's entirely orthogonal. It doesn't affect the cpu-exec part of icount, only the "timers" :) part. > What about the previous patch disabling icount for -smp? Does this > series supersede it or does it fix different concurrency issues? This is for making accesses to icount safe without holding the BQL. icount for -smp remains just as broken as before. Paolo