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

From: kys
Date: Fri Sep 22 2017 - 00:00:01 EST


From: Stephen Hemminger <stephen@xxxxxxxxxxxxxxxxxx>

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@xxxxxxxxxxxxx>
Signed-off-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>
---
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@xxxxxxxxxxxxx>
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@xxxxxxxxxxxxx>
+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@xxxxxxxxxxxxx>
+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