linux-kernel - Re: [PATCH v4] Drivers: hv: vmbus: Expose counters for interrupts and full conditions

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Date:   Thu, 14 Feb 2019 20:57:02 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     Michael Kelley <mikelley@...rosoft.com>
Cc:     kimbrownkd <kimbrownkd@...il.com>, Long Li <longli@...rosoft.com>,
        Sasha Levin <Alexander.Levin@...rosoft.com>,
        Dexuan Cui <decui@...rosoft.com>,
        Stephen Hemminger <sthemmin@...rosoft.com>,
        KY Srinivasan <kys@...rosoft.com>,
        Haiyang Zhang <haiyangz@...rosoft.com>,
        "devel@...uxdriverproject.org" <devel@...uxdriverproject.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v4] Drivers: hv: vmbus: Expose counters for interrupts
 and full conditions

On Mon, Feb 04, 2019 at 04:25:34PM +0000, Michael Kelley wrote:
>From: Kimberly Brown <kimbrownkd@...il.com> Sent: Sunday, February 3, 2019 11:13 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
>>
>> 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@...il.com>
>> ---
>>
>Reviewed-by:  Michael Kelley <mikelley@...rosoft.com>

Queued for hyperv-next, thanks Kimberly!

--
Thanks,
Sasha