From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:52981) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dK26X-0000Lc-6G for qemu-devel@nongnu.org; Sun, 11 Jun 2017 08:36:30 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dK26U-0005hJ-2q for qemu-devel@nongnu.org; Sun, 11 Jun 2017 08:36:29 -0400 Received: from roura.ac.upc.es ([147.83.33.10]:35780) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dK26T-0005ge-MT for qemu-devel@nongnu.org; Sun, 11 Jun 2017 08:36:26 -0400 From: =?utf-8?Q?Llu=C3=ADs_Vilanova?= References: <1496975122-16999-1-git-send-email-cota@braap.org> <1496975122-16999-3-git-send-email-cota@braap.org> Date: Sun, 11 Jun 2017 15:36:16 +0300 In-Reply-To: <1496975122-16999-3-git-send-email-cota@braap.org> (Emilio G. Cota's message of "Thu, 8 Jun 2017 22:25:17 -0400") Message-ID: <87poeaog5b.fsf@frigg.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH v8 2/7] cpu: allocate cpu->trace_dstate in place List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Emilio G. Cota" Cc: qemu-devel@nongnu.org, Richard Henderson , Stefan Hajnoczi Emilio G Cota writes: > There's little point in dynamically allocating the bitmap if we > know at compile-time the max number of events we want to support. > Thus, make room in the struct for the bitmap, which will make things > easier later: this paves the way for upcoming changes, in which > we'll use a u32 to fully capture cpu->trace_dstate. > This change also increases performance by saving a dereference and > improving locality--note that this is important since upcoming work > makes reading this bitmap fairly common. > Signed-off-by: Emilio G. Cota Reviewed-by: Llu=C3=ADs Vilanova > --- > include/qom/cpu.h | 9 +++------ > qom/cpu.c | 8 -------- > trace/control.c | 9 ++++++++- > 3 files changed, 11 insertions(+), 15 deletions(-) > diff --git a/include/qom/cpu.h b/include/qom/cpu.h > index 89ddb68..bc6e20f 100644 > --- a/include/qom/cpu.h > +++ b/include/qom/cpu.h > @@ -259,6 +259,7 @@ typedef void (*run_on_cpu_func)(CPUState *cpu, run_on= _cpu_data data); > struct qemu_work_item; =20 > #define CPU_UNSET_NUMA_NODE_ID -1 > +#define CPU_TRACE_DSTATE_MAX_EVENTS 32 =20 > /** > * CPUState: > @@ -373,12 +374,8 @@ struct CPUState { > struct KVMState *kvm_state; > struct kvm_run *kvm_run; =20 > - /* > - * Used for events with 'vcpu' and *without* the 'disabled' properti= es. > - * Dynamically allocated based on bitmap requried to hold up to > - * trace_get_vcpu_event_count() entries. > - */ > - unsigned long *trace_dstate; > + /* Used for events with 'vcpu' and *without* the 'disabled' properti= es */ > + DECLARE_BITMAP(trace_dstate, CPU_TRACE_DSTATE_MAX_EVENTS); =20 > /* TODO Move common fields from CPUArchState here. */ > int cpu_index; /* used by alpha TCG */ > diff --git a/qom/cpu.c b/qom/cpu.c > index 5069876..69fbb9c 100644 > --- a/qom/cpu.c > +++ b/qom/cpu.c > @@ -382,7 +382,6 @@ static void cpu_common_unrealizefn(DeviceState *dev, = Error **errp) =20 > static void cpu_common_initfn(Object *obj) > { > - uint32_t count; > CPUState *cpu =3D CPU(obj); > CPUClass *cc =3D CPU_GET_CLASS(obj); =20 > @@ -397,18 +396,11 @@ static void cpu_common_initfn(Object *obj) > QTAILQ_INIT(&cpu->breakpoints); > QTAILQ_INIT(&cpu->watchpoints); =20 > - count =3D trace_get_vcpu_event_count(); > - if (count) { > - cpu->trace_dstate =3D bitmap_new(count); > - } > - > cpu_exec_initfn(cpu); > } =20 > static void cpu_common_finalize(Object *obj) > { > - CPUState *cpu =3D CPU(obj); > - g_free(cpu->trace_dstate); > } =20 > static int64_t cpu_common_get_arch_id(CPUState *cpu) > diff --git a/trace/control.c b/trace/control.c > index 9b157b0..83740aa 100644 > --- a/trace/control.c > +++ b/trace/control.c > @@ -65,8 +65,15 @@ void trace_event_register_group(TraceEvent **events) > size_t i; > for (i =3D 0; events[i] !=3D NULL; i++) { > events[i]->id =3D next_id++; > - if (events[i]->vcpu_id !=3D TRACE_VCPU_EVENT_NONE) { > + if (events[i]->vcpu_id =3D=3D TRACE_VCPU_EVENT_NONE) { > + continue; > + } > + > + if (likely(next_vcpu_id < CPU_TRACE_DSTATE_MAX_EVENTS)) { > events[i]->vcpu_id =3D next_vcpu_id++; > + } else { > + error_report("WARNING: too many vcpu trace events; dropping = '%s'", > + events[i]->name); > } > } > event_groups =3D g_renew(TraceEventGroup, event_groups, nevent_group= s + 1); > --=20 > 2.7.4