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From: David Miller <davem@davemloft.net>
To: sunilmut@microsoft.com
Cc: kys@microsoft.com, haiyangz@microsoft.com,
	sthemmin@microsoft.com, sashal@kernel.org,
	mikelley@microsoft.com, netdev@vger.kernel.org,
	linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH net-next] hv_sock: perf: loop in send() to maximize bandwidth
Date: Wed, 22 May 2019 18:00:58 -0700 (PDT)	[thread overview]
Message-ID: <20190522.180058.887469871482412864.davem@davemloft.net> (raw)
In-Reply-To: <BN6PR21MB0465FA591662A8B580AEF7D9C0000@BN6PR21MB0465.namprd21.prod.outlook.com>

From: Sunil Muthuswamy <sunilmut@microsoft.com>
Date: Wed, 22 May 2019 23:10:44 +0000

> Currently, the hv_sock send() iterates once over the buffer, puts data into
> the VMBUS channel and returns. It doesn't maximize on the case when there
> is a simultaneous reader draining data from the channel. In such a case,
> the send() can maximize the bandwidth (and consequently minimize the cpu
> cycles) by iterating until the channel is found to be full.
> 
> Perf data:
> Total Data Transfer: 10GB/iteration
> Single threaded reader/writer, Linux hvsocket writer with Windows hvsocket
> reader
> Packet size: 64KB
> CPU sys time was captured using the 'time' command for the writer to send
> 10GB of data.
> 'Send Buffer Loop' is with the patch applied.
> The values below are over 10 iterations.
 ...
> Observation:
> 1. The avg throughput doesn't really change much with this change for this
> scenario. This is most probably because the bottleneck on throughput is
> somewhere else.
> 2. The average system (or kernel) cpu time goes down by 10%+ with this
> change, for the same amount of data transfer.
> 
> Signed-off-by: Sunil Muthuswamy <sunilmut@microsoft.com>

Applied.

      parent reply	other threads:[~2019-05-23  1:01 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-22 23:10 [PATCH net-next] hv_sock: perf: loop in send() to maximize bandwidth Sunil Muthuswamy
2019-05-22 23:31 ` Dexuan Cui
2019-05-23  1:00 ` David Miller [this message]

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