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authorKimberly Brown <kimbrownkd@gmail.com>2019-02-04 02:13:09 -0500
committerSasha Levin <sashal@kernel.org>2019-02-14 20:56:10 -0500
commit396ae57ef1ef978d1d21cdb7586ba184a3f22453 (patch)
tree28bdc8b7e25260feed3822e3bbc4f2fd1711cc7d /drivers/hv/ring_buffer.c
parent593db80390cf40f1b9dcc790020d2edae87183fb (diff)
Drivers: hv: vmbus: Expose counters for interrupts and full conditions
Counter values for per-channel interrupts and ring buffer full conditions are useful for investigating performance. Expose counters in sysfs for 2 types of guest to host interrupts: 1) Interrupts caused by the channel's outbound ring buffer transitioning from empty to not empty 2) Interrupts caused by the channel's inbound ring buffer transitioning from full to not full while a packet is waiting for enough buffer space to become available Expose 2 counters in sysfs for the number of times that write operations encountered a full outbound ring buffer: 1) The total number of write operations that encountered a full condition 2) The number of write operations that were the first to encounter a full condition Increment the outbound full condition counters in the hv_ringbuffer_write() function because, for most drivers, a full outbound ring buffer is detected in that function. Also increment the outbound full condition counters in the set_channel_pending_send_size() function. In the hv_sock driver, a full outbound ring buffer is detected and set_channel_pending_send_size() is called before hv_ringbuffer_write() is called. I tested this patch by confirming that the sysfs files were created and observing the counter values. The values seemed to increase by a reasonable amount when the Hyper-v related drivers were in use. Signed-off-by: Kimberly Brown <kimbrownkd@gmail.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/hv/ring_buffer.c')
-rw-r--r--drivers/hv/ring_buffer.c14
1 files changed, 13 insertions, 1 deletions
diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c
index 1f1a55e07733..9e8b31ccc142 100644
--- a/drivers/hv/ring_buffer.c
+++ b/drivers/hv/ring_buffer.c
@@ -74,8 +74,10 @@ static void hv_signal_on_write(u32 old_write, struct vmbus_channel *channel)
* This is the only case we need to signal when the
* ring transitions from being empty to non-empty.
*/
- if (old_write == READ_ONCE(rbi->ring_buffer->read_index))
+ if (old_write == READ_ONCE(rbi->ring_buffer->read_index)) {
+ ++channel->intr_out_empty;
vmbus_setevent(channel);
+ }
}
/* Get the next write location for the specified ring buffer. */
@@ -272,10 +274,19 @@ int hv_ringbuffer_write(struct vmbus_channel *channel,
* is empty since the read index == write index.
*/
if (bytes_avail_towrite <= totalbytes_towrite) {
+ ++channel->out_full_total;
+
+ if (!channel->out_full_flag) {
+ ++channel->out_full_first;
+ channel->out_full_flag = true;
+ }
+
spin_unlock_irqrestore(&outring_info->ring_lock, flags);
return -EAGAIN;
}
+ channel->out_full_flag = false;
+
/* Write to the ring buffer */
next_write_location = hv_get_next_write_location(outring_info);
@@ -530,6 +541,7 @@ void hv_pkt_iter_close(struct vmbus_channel *channel)
if (curr_write_sz <= pending_sz)
return;
+ ++channel->intr_in_full;
vmbus_setevent(channel);
}
EXPORT_SYMBOL_GPL(hv_pkt_iter_close);