From: Andrew Lunn <andrew@lunn.ch>
To: Christian Marangi <ansuelsmth@gmail.com>
Cc: Vincent Whitchurch <vincent.whitchurch@axis.com>,
Raju Rangoju <rajur@chelsio.com>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
Alexandre Torgue <alexandre.torgue@foss.st.com>,
Jose Abreu <joabreu@synopsys.com>,
Maxime Coquelin <mcoquelin.stm32@gmail.com>,
Ping-Ke Shih <pkshih@realtek.com>, Kalle Valo <kvalo@kernel.org>,
Simon Horman <horms@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Jiri Pirko <jiri@resnulli.us>, Hangbin Liu <liuhangbin@gmail.com>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-stm32@st-md-mailman.stormreply.com,
linux-arm-kernel@lists.infradead.org,
linux-wireless@vger.kernel.org
Subject: Re: [net-next PATCH 3/3] net: stmmac: increase TX coalesce timer to 5ms
Date: Fri, 22 Sep 2023 14:28:06 +0200 [thread overview]
Message-ID: <13bc074d-30c2-4bbf-8b4c-82f561c844b0@lunn.ch> (raw)
In-Reply-To: <20230922111247.497-3-ansuelsmth@gmail.com>
On Fri, Sep 22, 2023 at 01:12:47PM +0200, Christian Marangi wrote:
> Commit 8fce33317023 ("net: stmmac: Rework coalesce timer and fix
> multi-queue races") decreased the TX coalesce timer from 40ms to 1ms.
>
> This caused some performance regression on some target (regression was
> reported at least on ipq806x) in the order of 600mbps dropping from
> gigabit handling to only 200mbps.
>
> The problem was identified in the TX timer getting armed too much time.
> While this was fixed and improved in another commit, performance can be
> improved even further by increasing the timer delay a bit moving from
> 1ms to 5ms.
>
> The value is a good balance between battery saving by prevending too
> much interrupt to be generated and permitting good performance for
> internet oriented devices.
ethtool has a settings you can use for this:
ethtool -C|--coalesce devname [adaptive-rx on|off] [adaptive-tx on|off]
[rx-usecs N] [rx-frames N] [rx-usecs-irq N] [rx-frames-irq N]
[tx-usecs N] [tx-frames N] [tx-usecs-irq N] [tx-frames-irq N]
[stats-block-usecs N] [pkt-rate-low N] [rx-usecs-low N]
[rx-frames-low N] [tx-usecs-low N] [tx-frames-low N]
[pkt-rate-high N] [rx-usecs-high N] [rx-frames-high N]
[tx-usecs-high N] [tx-frames-high N] [sample-interval N]
[cqe-mode-rx on|off] [cqe-mode-tx on|off] [tx-aggr-max-bytes N]
[tx-aggr-max-frames N] [tx-aggr-time-usecs N]
If this is not implemented, i suggest you add support for it.
Changing the default might cause regressions. Say there is a VoIP
application which wants this low latency? It would be safer to allow
user space to configure it as wanted.
Andrew
next prev parent reply other threads:[~2023-09-22 12:28 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-22 11:12 [net-next PATCH 1/3] net: introduce napi_is_scheduled helper Christian Marangi
2023-09-22 11:12 ` [net-next PATCH 2/3] net: stmmac: improve TX timer arm logic Christian Marangi
2023-09-29 12:38 ` Vincent Whitchurch
2023-09-30 12:04 ` Christian Marangi
2023-09-22 11:12 ` [net-next PATCH 3/3] net: stmmac: increase TX coalesce timer to 5ms Christian Marangi
2023-09-22 12:28 ` Andrew Lunn [this message]
2023-09-22 12:39 ` Christian Marangi
2023-09-22 20:02 ` Dave Taht
2023-09-29 21:03 ` [net-next PATCH 1/3] net: introduce napi_is_scheduled helper Nambiar, Amritha
2023-09-30 11:59 ` Eric Dumazet
2023-09-30 12:11 ` Christian Marangi
2023-09-30 13:42 ` Eric Dumazet
2023-10-02 12:29 ` Christian Marangi
2023-10-02 12:35 ` Eric Dumazet
2023-10-02 12:43 ` Christian Marangi
2023-10-02 12:49 ` Eric Dumazet
2023-10-02 12:54 ` Christian Marangi
2023-10-02 12:56 ` Eric Dumazet
2023-10-02 12:59 ` Eric Dumazet
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