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Message-ID: <5db4e640-8165-d7bf-c6b6-192ea7edfafd@arm.com>
Date:   Mon, 27 Jun 2022 08:52:51 +0100
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Subject: Re: [PATCH net-next 1/4] time64.h: define PSEC_PER_NSEC and use it in
 tc-taprio
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To:     Vladimir Oltean <vladimir.oltean@nxp.com>, netdev@vger.kernel.org
Cc:     "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Xiaoliang Yang <xiaoliang.yang_1@nxp.com>,
        Claudiu Manoil <claudiu.manoil@nxp.com>,
        Alexandre Belloni <alexandre.belloni@bootlin.com>,
        UNGLinuxDriver@microchip.com, Andrew Lunn <andrew@lunn.ch>,
        Vivien Didelot <vivien.didelot@gmail.com>,
        Florian Fainelli <f.fainelli@gmail.com>,
        Michael Walle <michael@walle.cc>,
        Vinicius Costa Gomes <vinicius.gomes@intel.com>,
        Maxim Kochetkov <fido_max@inbox.ru>,
        Colin Foster <colin.foster@in-advantage.com>,
        Richie Pearn <richard.pearn@nxp.com>,
        linux-kernel@vger.kernel.org, Andy Lutomirski <luto@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>
References: <20220626120505.2369600-1-vladimir.oltean@nxp.com>
 <20220626120505.2369600-2-vladimir.oltean@nxp.com>
From:   Vincenzo Frascino <vincenzo.frascino@arm.com>
In-Reply-To: <20220626120505.2369600-2-vladimir.oltean@nxp.com>
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Hi Vladimir,

On 6/26/22 13:05, Vladimir Oltean wrote:
> Time-sensitive networking code needs to work with PTP times expressed in
> nanoseconds, and with packet transmission times expressed in
> picoseconds, since those would be fractional at higher than gigabit
> speed when expressed in nanoseconds.
> 
> Convert the existing uses in tc-taprio to a PSEC_PER_NSEC macro.
> 
> Cc: Andy Lutomirski <luto@kernel.org>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
> Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
> ---
>  include/vdso/time64.h  | 1 +
>  net/sched/sch_taprio.c | 4 ++--
>  2 files changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/include/vdso/time64.h b/include/vdso/time64.h
> index b40cfa2aa33c..f1c2d02474ae 100644
> --- a/include/vdso/time64.h
> +++ b/include/vdso/time64.h
> @@ -6,6 +6,7 @@
>  #define MSEC_PER_SEC	1000L
>  #define USEC_PER_MSEC	1000L
>  #define NSEC_PER_USEC	1000L
> +#define PSEC_PER_NSEC	1000L

Are you planning to use this definition in the vdso library code? If not, you
should define PSEC_PER_NSEC in "include/linux/time64.h". The vdso namespace
should contain only the definitions shared by the implementations of the kernel
and of the vdso library.

...
-- 
Regards,
Vincenzo