From: Simon Horman <horms@kernel.org>
To: Bartlomiej Dziag <bartlomiejdziag@gmail.com>
Cc: "Andrew Lunn" <andrew+netdev@lunn.ch>,
"David S. Miller" <davem@davemloft.net>,
"Eric Dumazet" <edumazet@google.com>,
"Jakub Kicinski" <kuba@kernel.org>,
"Paolo Abeni" <pabeni@redhat.com>,
"Maxime Coquelin" <mcoquelin.stm32@gmail.com>,
"Alexandre Torgue" <alexandre.torgue@foss.st.com>,
"Maxime Chevallier" <maxime.chevallier@bootlin.com>,
"Daniel Machon" <daniel.machon@microchip.com>,
"Wojciech Drewek" <wojciech.drewek@intel.com>,
"Oleksij Rempel" <o.rempel@pengutronix.de>,
"Alexis Lothoré" <alexis.lothore@bootlin.com>,
netdev@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] net: stmmac: Change the busy-wait loops timing
Date: Sat, 7 Jun 2025 17:21:10 +0100 [thread overview]
Message-ID: <20250607162110.GB197663@horms.kernel.org> (raw)
In-Reply-To: <20250606102100.12576-1-bartlomiejdziag@gmail.com>
On Fri, Jun 06, 2025 at 12:19:49PM +0200, Bartlomiej Dziag wrote:
> After writing a new value to the PTP_TAR or PTP_STSUR registers,
> the driver waits for the addend/adjust operations to complete.
> Sometimes, the first check operation fails, resulting in
> a 10 milliseconds busy-loop before performing the next check.
> Since updating the registers takes much less than 10 milliseconds,
> the kernel gets stuck unnecessarily. This may increase the CPU usage.
> Fix that with changing the busy-loop interval to 5 microseconds.
> The registers will be checked more often.
Hi Bartlomiej,
I am curious.
Does it always take much less than 10ms, or is that usually so.
If it is the former, then do we need to wait for in the order of
10000 x 5us = 50ms before giving up?
>
> Signed-off-by: Bartlomiej Dziag <bartlomiejdziag@gmail.com>
...
prev parent reply other threads:[~2025-06-07 16:21 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-06-06 10:19 Bartlomiej Dziag
2025-06-06 13:55 ` Andrew Lunn
2025-06-07 16:21 ` Simon Horman [this message]
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