RE: [PATCH v3] Drivers: hv: vmbus: Expose counters for interrupts and full conditions

[Michael Kelley]

From: Kimberly Brown <kimbrownkd@xxxxxxxxx> Sent: Wednesday, January 16, 2019 8:38 PM
> 
> 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
> 
> 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@xxxxxxxxx>
> ---
> Changes in v3:
>  - Used the outbound ring buffer spinlock to protect the the full
>    condition counters in set_channel_pending_send_size()
>  - Corrected the KernelVersion values for the new entries in
>    Documentation/ABI/stable/sysfs-bus-vmbus
> 
> Changes in v2:
>  - Added mailing lists to the cc list
>  - Removed the host to guest interrupt counters proposed in v1 because
>    they were not accurate
>  - Added full condition counters for the channel's outbound ring buffer
> 
>  Documentation/ABI/stable/sysfs-bus-vmbus | 33 ++++++++++++++++++++
>  drivers/hv/ring_buffer.c                 | 14 ++++++++-
>  drivers/hv/vmbus_drv.c                   | 32 ++++++++++++++++++++
>  include/linux/hyperv.h                   | 38 ++++++++++++++++++++++++
>  4 files changed, 116 insertions(+), 1 deletion(-)
> 

Reviewed-by: Michael Kelley <mikelley@xxxxxxxxxxxxx>