From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:35525) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eRxFG-0001fN-14 for qemu-devel@nongnu.org; Thu, 21 Dec 2017 04:34:31 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eRxFC-0003dT-2t for qemu-devel@nongnu.org; Thu, 21 Dec 2017 04:34:30 -0500 Received: from mx1.redhat.com ([209.132.183.28]:60374) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1eRxFB-0003cG-QV for qemu-devel@nongnu.org; Thu, 21 Dec 2017 04:34:26 -0500 Date: Thu, 21 Dec 2017 17:34:16 +0800 From: Fam Zheng Message-ID: <20171221093416.GI10812@lemon> References: <20171219084557.9801-1-peterx@redhat.com> <20171219084557.9801-11-peterx@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20171219084557.9801-11-peterx@redhat.com> Subject: Re: [Qemu-devel] [RFC v6 10/27] monitor: allow to use IO thread for parsing List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Xu Cc: qemu-devel@nongnu.org, Stefan Hajnoczi , "Daniel P . Berrange" , Paolo Bonzini , Juan Quintela , mdroth@linux.vnet.ibm.com, Eric Blake , Laurent Vivier , Markus Armbruster , marcandre.lureau@redhat.com, "Dr . David Alan Gilbert" On Tue, 12/19 16:45, Peter Xu wrote: > For each Monitor, add one field "use_io_thr" to show whether it will be > using the dedicated monitor IO thread to handle input/output. When set, > monitor IO parsing work will be offloaded to dedicated monitor IO > thread, rather than the original main loop thread. > > This only works for QMP. HMP will always be run on main loop thread. > > Currently we're still keeping use_io_thr to off always. Will turn it on > later at some point. > > One thing to mention is that we cannot set use_io_thr for every QMP > monitors. The problem is that MUXed typed chardevs may not work well > with it now. When MUX is used, frontend of chardev can be the monitor > plus something else. The only thing we know would be safe to be run > outside main thread so far is the monitor frontend. All the rest of the > frontends should still be run in main thread only. > > Signed-off-by: Peter Xu > --- > monitor.c | 41 ++++++++++++++++++++++++++++++++--------- > 1 file changed, 32 insertions(+), 9 deletions(-) > > diff --git a/monitor.c b/monitor.c > index 4ebd83fd94..4b2bee773f 100644 > --- a/monitor.c > +++ b/monitor.c > @@ -190,6 +190,7 @@ struct Monitor { > int flags; > int suspend_cnt; > bool skip_flush; > + bool use_io_thr; > > QemuMutex out_lock; > QString *outbuf; > @@ -573,7 +574,8 @@ static void monitor_qapi_event_init(void) > > static void handle_hmp_command(Monitor *mon, const char *cmdline); > > -static void monitor_data_init(Monitor *mon, bool skip_flush) > +static void monitor_data_init(Monitor *mon, bool skip_flush, > + bool use_io_thr) > { > memset(mon, 0, sizeof(Monitor)); > qemu_mutex_init(&mon->out_lock); > @@ -581,6 +583,7 @@ static void monitor_data_init(Monitor *mon, bool skip_flush) > /* Use *mon_cmds by default. */ > mon->cmd_table = mon_cmds; > mon->skip_flush = skip_flush; > + mon->use_io_thr = use_io_thr; > } > > static void monitor_data_destroy(Monitor *mon) > @@ -601,7 +604,7 @@ char *qmp_human_monitor_command(const char *command_line, bool has_cpu_index, > char *output = NULL; > Monitor *old_mon, hmp; > > - monitor_data_init(&hmp, true); > + monitor_data_init(&hmp, true, false); > > old_mon = cur_mon; > cur_mon = &hmp; > @@ -4103,8 +4106,9 @@ void error_vprintf_unless_qmp(const char *fmt, va_list ap) > void monitor_init(Chardev *chr, int flags) > { > Monitor *mon = g_malloc(sizeof(*mon)); > + GMainContext *context; > > - monitor_data_init(mon, false); > + monitor_data_init(mon, false, false); > > qemu_chr_fe_init(&mon->chr, chr, &error_abort); > mon->flags = flags; > @@ -4116,19 +4120,38 @@ void monitor_init(Chardev *chr, int flags) > monitor_read_command(mon, 0); > } > > + if (mon->use_io_thr) { > + /* > + * When use_io_thr is set, we use the global shared dedicated > + * IO thread for this monitor to handle input/output. > + */ > + context = monitor_io_context_get(); > + /* We should have inited globals before reaching here. */ > + assert(context); > + } else { > + /* The default main loop, which is the main thread */ > + context = NULL; > + } > + > + /* > + * Add the monitor before running it (which is triggered by > + * qemu_chr_fe_set_handlers), otherwise one monitor may find > + * itself not on the mon_list when running. > + */ > + qemu_mutex_lock(&monitor_lock); > + QTAILQ_INSERT_HEAD(&mon_list, mon, entry); > + qemu_mutex_unlock(&monitor_lock); > + > if (monitor_is_qmp(mon)) { > - qemu_chr_fe_set_handlers(&mon->chr, monitor_can_read, monitor_qmp_read, > - monitor_qmp_event, NULL, mon, NULL, true); > qemu_chr_fe_set_echo(&mon->chr, true); > json_message_parser_init(&mon->qmp.parser, handle_qmp_command); > + qemu_chr_fe_set_handlers(&mon->chr, monitor_can_read, monitor_qmp_read, > + monitor_qmp_event, NULL, mon, context, true); > } else { > + assert(!context); /* HMP does not support IOThreads */ > qemu_chr_fe_set_handlers(&mon->chr, monitor_can_read, monitor_read, > monitor_event, NULL, mon, NULL, true); > } > - > - qemu_mutex_lock(&monitor_lock); > - QLIST_INSERT_HEAD(&mon_list, mon, entry); > - qemu_mutex_unlock(&monitor_lock); > } > > void monitor_cleanup(void) > -- > 2.14.3 > Reviewed-by: Fam Zheng