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Date:   Tue, 25 Oct 2022 15:10:31 -0700
From:   Jakub Kicinski <kuba@kernel.org>
To:     Nick Child <nnac123@linux.ibm.com>
Cc:     netdev@vger.kernel.org, nick.child@ibm.com, dave.taht@gmail.com
Subject: Re: [RFC PATCH net-next 0/1] ibmveth: Implement BQL
Message-ID: <20221025151031.67f06127@kernel.org>
In-Reply-To: <b4492820-a2d5-7f86-75e4-cb344e050a8f@linux.ibm.com>
References: <20221024213828.320219-1-nnac123@linux.ibm.com>
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        <b4492820-a2d5-7f86-75e4-cb344e050a8f@linux.ibm.com>
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On Tue, 25 Oct 2022 15:03:03 -0500 Nick Child wrote:
> Th qdisc is default pfifo_fast.

You need a more advanced qdisc to seen an effect. Try fq.
BQL tries to keep the NIC queue (fifo) as short as possible
to hold packets in the qdisc. But if the qdisc is also just
a fifo there's no practical difference.

I have no practical experience with BQL on virtualized NICs 
tho, so unsure what gains you should expect to see..