From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:48979) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1f3fkp-0000WN-DV for qemu-devel@nongnu.org; Wed, 04 Apr 2018 06:35:00 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1f3fkm-00067X-7p for qemu-devel@nongnu.org; Wed, 04 Apr 2018 06:34:59 -0400 Received: from mail-wr0-x244.google.com ([2a00:1450:400c:c0c::244]:40790) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1f3fkl-00065B-V8 for qemu-devel@nongnu.org; Wed, 04 Apr 2018 06:34:56 -0400 Received: by mail-wr0-x244.google.com with SMTP id n2so18465438wrj.7 for ; Wed, 04 Apr 2018 03:34:55 -0700 (PDT) References: <20180111125444.6498-1-pbonzini@redhat.com> From: Alex =?utf-8?Q?Benn=C3=A9e?= In-reply-to: <20180111125444.6498-1-pbonzini@redhat.com> Date: Wed, 04 Apr 2018 11:34:53 +0100 Message-ID: <87lge3cl9u.fsf@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH] cpus: unify qemu_*_wait_io_event List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini Cc: qemu-devel@nongnu.org, Pavel Dovgalyuk Paolo Bonzini writes: > Except for round-robin TCG, every other accelerator is using more or > less the same code around qemu_wait_io_event_common. The exception > is HAX, which also has to eat the dummy APC that is queued by > qemu_cpu_kick_thread. > > We can add the SleepEx call to qemu_wait_io_event under "if > (!tcg_enabled())", since that is the condition that is used in > qemu_cpu_kick_thread, and unify the function for KVM, HAX, HVF and > multi-threaded TCG. Single-threaded TCG code can also be simplified > since it is only used in the round-robin, sleep-if-all-CPUs-idle case. > > Signed-off-by: Paolo Bonzini I had trouble applying this patch but the change seems sane to me Acked-by: Alex Benn=C3=A9e > --- > cpus.c | 49 +++++++++++++++++-------------------------------- > 1 file changed, 17 insertions(+), 32 deletions(-) > > diff --git a/cpus.c b/cpus.c > index 440b9291f5..3b6c9879ec 100644 > --- a/cpus.c > +++ b/cpus.c > @@ -911,7 +911,8 @@ static void kick_tcg_thread(void *opaque) > > static void start_tcg_kick_timer(void) > { > - if (!mttcg_enabled && !tcg_kick_vcpu_timer && CPU_NEXT(first_cpu)) { > + assert(!mttcg_enabled); > + if (!tcg_kick_vcpu_timer && CPU_NEXT(first_cpu)) { > tcg_kick_vcpu_timer =3D timer_new_ns(QEMU_CLOCK_VIRTUAL, > kick_tcg_thread, NULL); > timer_mod(tcg_kick_vcpu_timer, qemu_tcg_next_kick()); > @@ -920,6 +921,7 @@ static void start_tcg_kick_timer(void) > > static void stop_tcg_kick_timer(void) > { > + assert(!mttcg_enabled); > if (tcg_kick_vcpu_timer) { > timer_del(tcg_kick_vcpu_timer); > tcg_kick_vcpu_timer =3D NULL; > @@ -1154,18 +1156,9 @@ static void qemu_wait_io_event_common(CPUState *cp= u) > process_queued_cpu_work(cpu); > } > > -static bool qemu_tcg_should_sleep(CPUState *cpu) > +static void qemu_tcg_rr_wait_io_event(CPUState *cpu) > { > - if (mttcg_enabled) { > - return cpu_thread_is_idle(cpu); > - } else { > - return all_cpu_threads_idle(); > - } > -} > - > -static void qemu_tcg_wait_io_event(CPUState *cpu) > -{ > - while (qemu_tcg_should_sleep(cpu)) { > + while (all_cpu_threads_idle()) { > stop_tcg_kick_timer(); > qemu_cond_wait(cpu->halt_cond, &qemu_global_mutex); > } > @@ -1175,20 +1168,18 @@ static void qemu_tcg_wait_io_event(CPUState *cpu) > qemu_wait_io_event_common(cpu); > } > > -static void qemu_kvm_wait_io_event(CPUState *cpu) > +static void qemu_wait_io_event(CPUState *cpu) > { > while (cpu_thread_is_idle(cpu)) { > qemu_cond_wait(cpu->halt_cond, &qemu_global_mutex); > } > > - qemu_wait_io_event_common(cpu); > -} > - > -static void qemu_hvf_wait_io_event(CPUState *cpu) > -{ > - while (cpu_thread_is_idle(cpu)) { > - qemu_cond_wait(cpu->halt_cond, &qemu_global_mutex); > +#ifdef _WIN32 > + /* Eat dummy APC queued by qemu_cpu_kick_thread. */ > + if (!tcg_enabled()) { > + SleepEx(0, TRUE); > } > +#endif > qemu_wait_io_event_common(cpu); > } > > @@ -1224,7 +1215,7 @@ static void *qemu_kvm_cpu_thread_fn(void *arg) > cpu_handle_guest_debug(cpu); > } > } > - qemu_kvm_wait_io_event(cpu); > + qemu_wait_io_event(cpu); > } while (!cpu->unplug || cpu_can_run(cpu)); > > qemu_kvm_destroy_vcpu(cpu); > @@ -1270,7 +1261,7 @@ static void *qemu_dummy_cpu_thread_fn(void *arg) > exit(1); > } > qemu_mutex_lock_iothread(); > - qemu_wait_io_event_common(cpu); > + qemu_wait_io_event(cpu); > } > > return NULL; > @@ -1487,7 +1478,7 @@ static void *qemu_tcg_rr_cpu_thread_fn(void *arg) > atomic_mb_set(&cpu->exit_request, 0); > } > > - qemu_tcg_wait_io_event(cpu ? cpu : QTAILQ_FIRST(&cpus)); > + qemu_tcg_rr_wait_io_event(cpu ? cpu : QTAILQ_FIRST(&cpus)); > deal_with_unplugged_cpus(); > } > > @@ -1518,13 +1509,7 @@ static void *qemu_hax_cpu_thread_fn(void *arg) > } > } > > - while (cpu_thread_is_idle(cpu)) { > - qemu_cond_wait(cpu->halt_cond, &qemu_global_mutex); > - } > -#ifdef _WIN32 > - SleepEx(0, TRUE); > -#endif > - qemu_wait_io_event_common(cpu); > + qemu_wait_io_event(cpu); > } > return NULL; > } > @@ -1561,7 +1546,7 @@ static void *qemu_hvf_cpu_thread_fn(void *arg) > cpu_handle_guest_debug(cpu); > } > } > - qemu_hvf_wait_io_event(cpu); > + qemu_wait_io_event(cpu); > } while (!cpu->unplug || cpu_can_run(cpu)); > > hvf_vcpu_destroy(cpu); > @@ -1640,7 +1625,7 @@ static void *qemu_tcg_cpu_thread_fn(void *arg) > } > > atomic_mb_set(&cpu->exit_request, 0); > - qemu_tcg_wait_io_event(cpu); > + qemu_wait_io_event(cpu); > } > > return NULL; -- Alex Benn=C3=A9e