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Date: Sat, 24 May 2025 22:59:28 +0100
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Subject: Re: [PATCH net-next v3 6/8] gve: Add rx hardware timestamp expansion
To: Harshitha Ramamurthy <hramamurthy@google.com>, netdev@vger.kernel.org
Cc: davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
 pabeni@redhat.com, jeroendb@google.com, andrew+netdev@lunn.ch,
 willemb@google.com, ziweixiao@google.com, pkaligineedi@google.com,
 yyd@google.com, joshwash@google.com, shailend@google.com, linux@treblig.org,
 thostet@google.com, jfraker@google.com, richardcochran@gmail.com,
 jdamato@fastly.com, horms@kernel.org, linux-kernel@vger.kernel.org
References: <20250522235737.1925605-1-hramamurthy@google.com>
 <20250522235737.1925605-7-hramamurthy@google.com>
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From: Vadim Fedorenko <vadim.fedorenko@linux.dev>
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On 23/05/2025 00:57, Harshitha Ramamurthy wrote:
> From: John Fraker <jfraker@google.com>
> 
> Allow the rx path to recover the high 32 bits of the full 64 bit rx
> timestamp.
> 
> Use the low 32 bits of the last synced nic time and the 32 bits of the
> timestamp provided in the rx descriptor to generate a difference, which
> is then applied to the last synced nic time to reconstruct the complete
> 64-bit timestamp.
> 
> This scheme remains accurate as long as no more than ~2 seconds have
> passed between the last read of the nic clock and the timestamping
> application of the received packet.
> 
> Signed-off-by: John Fraker <jfraker@google.com>
> Signed-off-by: Ziwei Xiao <ziweixiao@google.com>
> Reviewed-by: Willem de Bruijn <willemb@google.com>
> Signed-off-by: Harshitha Ramamurthy <hramamurthy@google.com>

Reviewed-by: Vadim Fedorenko <vadim.fedorenko@linux.dev>