linux-kernel - [PATCH 2/2] Drivers: hv: vmbus: Expose per-channel interrupts and events counters

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Message-Id: <20170922035850.6689-2-kys@exchange.microsoft.com>
Date:   Thu, 21 Sep 2017 20:58:50 -0700
From:   kys@...hange.microsoft.com
To:     gregkh@...uxfoundation.org, linux-kernel@...r.kernel.org,
        devel@...uxdriverproject.org, olaf@...fle.de, apw@...onical.com,
        vkuznets@...hat.com, jasowang@...hat.com,
        leann.ogasawara@...onical.com, marcelo.cerri@...onical.com,
        sthemmin@...rosoft.com
Cc:     Stephen Hemminger <stephen@...workplumber.org>,
        "K . Y . Srinivasan" <kys@...rosoft.com>
Subject: [PATCH 2/2] Drivers: hv: vmbus: Expose per-channel interrupts and events counters

From: Stephen Hemminger <stephen@...workplumber.org>

When investigating performance, it is useful to be able to look at
the number of host and guest events per-channel. This is equivalent
to per-device interrupt statistics.

Signed-off-by: Stephen Hemminger <sthemmin@...rosoft.com>
Signed-off-by: K. Y. Srinivasan <kys@...rosoft.com>
---
 Documentation/ABI/stable/sysfs-bus-vmbus | 14 ++++++++++++++
 drivers/hv/connection.c                  |  2 ++
 drivers/hv/vmbus_drv.c                   | 18 ++++++++++++++++++
 include/linux/hyperv.h                   |  4 ++++
 4 files changed, 38 insertions(+)

diff --git a/Documentation/ABI/stable/sysfs-bus-vmbus b/Documentation/ABI/stable/sysfs-bus-vmbus
index 0ebd8a1537a0..d4eca1717adb 100644
--- a/Documentation/ABI/stable/sysfs-bus-vmbus
+++ b/Documentation/ABI/stable/sysfs-bus-vmbus
@@ -97,3 +97,17 @@ KernelVersion:	4.14
 Contact:	Stephen Hemminger <sthemmin@...rosoft.com>
 Description:	Bytes availabble to write
 Users:		Debuggig tools
+
+What:		/sys/bus/vmbus/devices/vmbus_*/channels/relid/events
+Date:		September. 2017
+KernelVersion:	4.14
+Contact:	Stephen Hemminger <sthemmin@...rosoft.com>
+Description:	Number of times we have signaled the host
+Users:		Debuggig tools
+
+What:		/sys/bus/vmbus/devices/vmbus_*/channels/relid/interrupts
+Date:		September. 2017
+KernelVersion:	4.14
+Contact:	Stephen Hemminger <sthemmin@...rosoft.com>
+Description:	Number of times we have taken an interrupt (incoming)
+Users:		Debuggig tools
diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
index 59c11ff90d12..2bb0d03c5212 100644
--- a/drivers/hv/connection.c
+++ b/drivers/hv/connection.c
@@ -406,6 +406,8 @@ void vmbus_set_event(struct vmbus_channel *channel)
 	if (!channel->is_dedicated_interrupt)
 		vmbus_send_interrupt(child_relid);
 
+	++channel->sig_events;
+
 	hv_do_hypercall(HVCALL_SIGNAL_EVENT, channel->sig_event, NULL);
 }
 EXPORT_SYMBOL_GPL(vmbus_set_event);
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index c126d3937414..88c4f5e98fc9 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -945,6 +945,8 @@ static void vmbus_chan_sched(struct hv_per_cpu_context *hv_cpu)
 			if (channel->rescind)
 				continue;
 
+			++channel->interrupts;
+
 			switch (channel->callback_mode) {
 			case HV_CALL_ISR:
 				vmbus_channel_isr(channel);
@@ -1238,6 +1240,20 @@ static ssize_t channel_latency_show(const struct vmbus_channel *channel,
 }
 VMBUS_CHAN_ATTR(latency, S_IRUGO, channel_latency_show, NULL);
 
+static ssize_t channel_interrupts_show(const struct vmbus_channel *channel, char *buf)
+{
+	return sprintf(buf, "%u\n", channel->interrupts);
+}
+VMBUS_CHAN_ATTR(interrupts, S_IRUGO, channel_interrupts_show, NULL);
+
+static ssize_t channel_events_show(const struct vmbus_channel *channel, char *buf)
+{
+	return sprintf(buf, "%u\n", channel->sig_events);
+}
+VMBUS_CHAN_ATTR(events, S_IRUGO, channel_events_show, NULL);
+
+
+
 static struct attribute *vmbus_chan_attrs[] = {
 	&chan_attr_out_mask.attr,
 	&chan_attr_in_mask.attr,
@@ -1246,6 +1262,8 @@ static struct attribute *vmbus_chan_attrs[] = {
 	&chan_attr_cpu.attr,
 	&chan_attr_pending.attr,
 	&chan_attr_latency.attr,
+	&chan_attr_interrupts.attr,
+	&chan_attr_events.attr,
 	NULL
 };
 
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index 91c88e0e771e..d7c85a475c46 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -731,6 +731,10 @@ struct vmbus_channel {
 
 	struct vmbus_close_msg close_msg;
 
+	/* Statistics */
+	unsigned int	interrupts;	/* Host to Guest interrupts */
+	unsigned int	sig_events;	/* Guest to Host events */
+
 	/* Channel callback's invoked in softirq context */
 	struct tasklet_struct callback_event;
 	void (*onchannel_callback)(void *context);
-- 
2.14.1