From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34908) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cdyxV-0003X6-9S for qemu-devel@nongnu.org; Wed, 15 Feb 2017 07:45:22 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cdyxQ-0004Ml-EB for qemu-devel@nongnu.org; Wed, 15 Feb 2017 07:45:21 -0500 Received: from mail.ispras.ru ([83.149.199.45]:56780) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cdyxQ-0004Lt-6O for qemu-devel@nongnu.org; Wed, 15 Feb 2017 07:45:16 -0500 From: "Pavel Dovgalyuk" References: <20170129210910.6333-1-pbonzini@redhat.com> <0775ca1e-ecdb-39a1-d2e9-6e410f0d4e54@redhat.com> In-Reply-To: <0775ca1e-ecdb-39a1-d2e9-6e410f0d4e54@redhat.com> Date: Wed, 15 Feb 2017 15:45:16 +0300 Message-ID: <000c01d28789$5b942330$12bc6990$@ru> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Content-Language: ru Subject: Re: [Qemu-devel] [RFC/RFT PATCH 0/7] cpu-exec: simplify cpu_exec and remove some icount special cases List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: 'Paolo Bonzini' , qemu-devel@nongnu.org Cc: serge.fdrv@gmail.com, pavel.dovgaluk@ispras.ru, peter.maydell@linaro.org > From: Paolo Bonzini [mailto:paolo.bonzini@gmail.com] On Behalf Of Paolo Bonzini > On 29/01/2017 22:09, Paolo Bonzini wrote: > > The series includes three parts: > > > > 1-2: fix two bugs, the first one pretty bad, the second seems > > to be theoretical only. > > > > 3-5: simplify cpu_exec. This builds on Sergey's conversion > > of cpu_exec to a simple top-down logic, making the phases > > clearer and saving on the cost of siglongjmp in the meanwhile. > > I'll include these five in my next pull request. Review for patch 6 is > welcome! I've tested all 7 and briefly looked at their code. Do you need official reviewed-by? Pavel Dovgalyuk > > > 6-7: these are intended to be a base for Pavel's record/replay > > fixes. The main thing I noticed while reviewing is that icount > > is redoing (with u16.high) a lot of things that tcg_exit_req is > > doing too. This is because, at the time icount was introduced, > > tcg_exit_req didn't exist and QEMU instead unwound chained TBs > > through POSIX signals. But now we have essentially two ways to > > do the same thing with subtly different invariants or downright > > bugs (such as the one fixed by patch 1). Patch 6 therefore > > unifies tcg_exit_req and the icount interrupt flag. It saves a > > handful of instructions per TB in icount mode and generally > > makes icount mode "less special", which is a good thing since > > no one seems to understand it well. Patch 7 then removes another > > EXCP_INTERRUPT/cpu_loop_exit pair; by exiting to main loop simply > > through cpu->exit_request, hopefully it fixes one of the issues that > > Pavel was seeing. > > > > For now I've tested this only on an aarch64 Linux image (with > > and without -icount). Thanks, > > > > Paolo > > > > Paolo Bonzini (7): > > cpu-exec: fix jmp_first out-of-bounds access with icount > > cpu-exec: tighten barrier on TCG_EXIT_REQUESTED > > cpu-exec: avoid cpu_loop_exit in cpu_handle_interrupt > > cpu-exec: avoid repeated sigsetjmp on interrupts > > cpu-exec: remove outermost infinite loop > > cpu-exec: unify icount_decr and tcg_exit_req > > cpu-exec: centralize exiting to the main loop > > > > cpu-exec.c | 153 +++++++++++++++++++++------------------------- > > include/exec/exec-all.h | 1 + > > include/exec/gen-icount.h | 53 ++++++++-------- > > include/qom/cpu.h | 15 +++-- > > qom/cpu.c | 2 +- > > tcg/tcg.h | 1 - > > translate-all.c | 2 +- > > translate-common.c | 13 ++-- > > 8 files changed, 109 insertions(+), 131 deletions(-) > >