From mboxrd@z Thu Jan 1 00:00:00 1970 From: Prerna Saxena Subject: [RFC v4][PATCH 3/3] Support for dynamically enabling/disabling trace events. Date: Thu, 24 Jun 2010 17:04:53 +0530 Message-ID: <20100624170453.344fb729@zephyr> References: <20100624164930.7859b779@zephyr> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: Anthony Liguori , Stefan Hajnoczi , kvm@vger.kernel.org, Jan Kiszka , Luiz Capitulino , Maneesh Soni , Ananth Narayan To: qemu-devel@nongnu.org Return-path: Received: from e23smtp04.au.ibm.com ([202.81.31.146]:47231 "EHLO e23smtp04.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752205Ab0FXLfB (ORCPT ); Thu, 24 Jun 2010 07:35:01 -0400 Received: from d23relay05.au.ibm.com (d23relay05.au.ibm.com [202.81.31.247]) by e23smtp04.au.ibm.com (8.14.4/8.13.1) with ESMTP id o5OBUjSm014965 for ; Thu, 24 Jun 2010 21:30:45 +1000 Received: from d23av03.au.ibm.com (d23av03.au.ibm.com [9.190.234.97]) by d23relay05.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id o5OBYxG7397432 for ; Thu, 24 Jun 2010 21:34:59 +1000 Received: from d23av03.au.ibm.com (loopback [127.0.0.1]) by d23av03.au.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id o5OBYw15024899 for ; Thu, 24 Jun 2010 21:34:59 +1000 In-Reply-To: <20100624164930.7859b779@zephyr> Sender: kvm-owner@vger.kernel.org List-ID: This patch adds support for dynamically enabling/disabling of trace events. This is done by internally maintaining each trace event's state, and permitting logging of data from a trace event only if it is in an 'active' state. Monitor commands added : 1) info trace-events : to view all available trace events and their state. 2) trace-event NAME on|off : to enable/disable data logging from a given trace event. Eg, trace-event paio_submit off disables logging of data when paio_submit is hit. By default, all trace-events are disabled. One can enable desired trace-events via the monitor. Signed-off-by: Prerna Saxena --- monitor.c | 16 ++++++++++++++++ qemu-monitor.hx | 18 ++++++++++++++++++ simpletrace.c | 41 +++++++++++++++++++++++++++++++++++++++++ tracetool | 33 +++++++++++++++++++++++++++++---- 4 files changed, 104 insertions(+), 4 deletions(-) diff --git a/monitor.c b/monitor.c index 8b60830..19b1ed7 100644 --- a/monitor.c +++ b/monitor.c @@ -548,6 +548,15 @@ static void do_commit(Monitor *mon, const QDict *qdict) } } +#ifdef CONFIG_SIMPLE_TRACE +static void do_change_trace_event_state(Monitor *mon, const QDict *qdict) +{ + const char *tp_name = qdict_get_str(qdict, "name"); + bool new_state = qdict_get_bool(qdict, "option"); + change_trace_event_state(tp_name, new_state); +} +#endif + static void user_monitor_complete(void *opaque, QObject *ret_data) { MonitorCompletionData *data = (MonitorCompletionData *)opaque; @@ -2791,6 +2800,13 @@ static const mon_cmd_t info_cmds[] = { .help = "show current contents of trace buffer", .mhandler.info = do_info_trace, }, + { + .name = "trace-events", + .args_type = "", + .params = "", + .help = "show available trace-events & their state", + .mhandler.info = do_info_all_trace_events, + }, #endif { .name = NULL, diff --git a/qemu-monitor.hx b/qemu-monitor.hx index 766c30f..0fedcf9 100644 --- a/qemu-monitor.hx +++ b/qemu-monitor.hx @@ -117,6 +117,8 @@ show device tree #ifdef CONFIG_SIMPLE_TRACE @item info trace show contents of trace buffer +@item info trace-events +show available trace events and their state #endif @end table ETEXI @@ -225,6 +227,22 @@ STEXI @item logfile @var{filename} @findex logfile Output logs to @var{filename}. +#ifdef CONFIG_SIMPLE_TRACE +ETEXI + + { + .name = "trace-event", + .args_type = "name:s,option:b", + .params = "name on|off", + .help = "changes status of a specific trace event", + .mhandler.cmd = do_change_trace_event_state, + }, + +STEXI +@item trace-event +@findex trace-event +changes status of a trace event +#endif ETEXI { diff --git a/simpletrace.c b/simpletrace.c index 5734d15..57c41fc 100644 --- a/simpletrace.c +++ b/simpletrace.c @@ -24,6 +24,11 @@ static void trace(TraceEventID event, unsigned long x1, unsigned long x2, unsigned long x3, unsigned long x4, unsigned long x5) { TraceRecord *rec = &trace_buf[trace_idx]; + + if (!trace_list[event].state) { + return; + } + rec->event = event; rec->x1 = x1; rec->x2 = x2; @@ -74,3 +79,39 @@ void do_info_trace(Monitor *mon) trace_buf[i].x3, trace_buf[i].x4, trace_buf[i].x5); } } + +void do_info_all_trace_events(Monitor *mon) +{ + unsigned int i; + + for (i = 0; i < NR_TRACE_EVENTS; i++) { + monitor_printf(mon, "%s [Event ID %u] : state %u\n", + trace_list[i].tp_name, i, trace_list[i].state); + } +} + +static TraceEvent* find_trace_event_by_name(const char *tname) +{ + unsigned int i; + + if (!tname) { + return NULL; + } + + for (i = 0; i < NR_TRACE_EVENTS; i++) { + if (!strcmp(trace_list[i].tp_name, tname)) { + return &trace_list[i]; + } + } + return NULL; /* indicates end of list reached without a match */ +} + +void change_trace_event_state(const char *tname, bool tstate) +{ + TraceEvent *tp; + + tp = find_trace_event_by_name(tname); + if (tp) { + tp->state = tstate; + } +} diff --git a/tracetool b/tracetool index 6f8f8a9..9e8dbd8 100755 --- a/tracetool +++ b/tracetool @@ -123,14 +123,23 @@ linetoc_end_nop() linetoh_begin_simple() { cat < + typedef unsigned int TraceEventID; +typedef struct { + const char *tp_name; + bool state; +} TraceEvent; + void trace1(TraceEventID event, unsigned long x1); void trace2(TraceEventID event, unsigned long x1, unsigned long x2); void trace3(TraceEventID event, unsigned long x1, unsigned long x2, unsigned long x3); void trace4(TraceEventID event, unsigned long x1, unsigned long x2, unsigned long x3, unsigned long x4); void trace5(TraceEventID event, unsigned long x1, unsigned long x2, unsigned long x3, unsigned long x4, unsigned long x5); void do_info_trace(Monitor *mon); +void do_info_all_trace_events(Monitor *mon); +void change_trace_event_state(const char *tname, bool tstate); EOF simple_event_num=0 @@ -163,22 +172,38 @@ EOF linetoh_end_simple() { - return + cat <