Re: [Qemu-devel] [PATCH v1] trace: add qemu_system_powerdown_request and qemu_system_shutdown_request trace events

["yangzy.fnst@cn.fujitsu.com" <yangzy.fnst@cn.fujitsu.com>]

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> -----Original Message-----
> From: Yang, Zhiyong/杨 志勇
> Sent: Wednesday, June 11, 2014 10:43 PM
> To: qemu-devel@nongnu.org
> Cc: Yang, Zhiyong/杨 志勇; peter.maydell@linaro.org;
> mdroth@linux.vnet.ibm.com; jforbes@redhat.com
> Subject: [Qemu-devel] [PATCH v1] trace: add
> qemu_system_powerdown_request and
> qemu_system_shutdown_request trace events
> 
> We have the experience that the guest doesn't stop successfully though it
> was instructed to shut down.
> 
> The root cause may be not in QEMU mostly.  However, QEMU is often
> suspected at the beginning just because the issue occurred in virtualization
> environment.
> 
> Therefore, we need to affirm that QEMU received the shutdown request
> and raised ACPI irq from "virsh shutdown" command, virt-manger or
> stopping QEMU process to the VM .
> So that we can affirm the problems was belonged to the Guset OS rather
> than the QEMU itself.
> 
> When we stop guests by "virsh shutdown" command or virt-manger, or
> stopping QEMU process, qemu_system_powerdown_request() or
> qemu_system_shutdown_request() is called. Then the below functions in
> main_loop_should_exit() of Vl.c are called roughly in the following order.
> 
> 	if (qemu_powerdown_requested())
> 		qemu_system_powerdown()
> 			monitor_protocol_event(QEVENT_POWERDOWN, NULL)
> 
> 	OR
> 
> 	if(qemu_shutdown_requested()}
> 		monitor_protocol_event(QEVENT_SHUTDOWN, NULL);
> 
> The tracepoint of monitor_protocol_event() already exists, but no
> tracepoints are defined for qemu_system_powerdown_request() and
> qemu_system_shutdown_request(). So this patch adds two tracepoints
> for the two functions. We believe that it will become much easier to isolate
> the problem mentioned above by these tracepoints.
> 
> 
> Signed-off-by: Yang Zhiyong <yangzy.fnst@cn.fujitsu.com>
> 
> ---
>  trace-events |    2 ++
>  vl.c         |    2 ++
>  2 files changed, 4 insertions(+), 0 deletions(-)
> 
> diff --git a/trace-events b/trace-events index 2c5b307..d642cc4 100644
> --- a/trace-events
> +++ b/trace-events
> @@ -511,6 +511,8 @@ g_malloc(size_t size, void *ptr) "size %zu ptr %p"
>  g_realloc(void *ptr, size_t size, void *newptr) "ptr %p size %zu
> newptr %p"
>  g_free(void *ptr) "ptr %p"
>  system_wakeup_request(int reason) "reason=%d"
> +qemu_system_shutdown_request(void) ""
> +qemu_system_powerdown_request(void) ""
> 
>  # block/qcow2.c
>  qcow2_writev_start_req(void *co, int64_t sector, int nb_sectors) "co %p
> sector %" PRIx64 " nb_sectors %d"
> diff --git a/vl.c b/vl.c
> index 709d8cd..aed0868 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -1982,6 +1982,7 @@ void qemu_system_killed(int signal, pid_t pid)
> 
>  void qemu_system_shutdown_request(void)
>  {
> +    trace_qemu_system_shutdown_request();
>      shutdown_requested = 1;
>      qemu_notify_event();
>  }
> @@ -1994,6 +1995,7 @@ static void qemu_system_powerdown(void)
> 
>  void qemu_system_powerdown_request(void)
>  {
> +    trace_qemu_system_powerdown_request();
>      powerdown_requested = 1;
>      qemu_notify_event();
>  }
> --
> 1.7.1