From: Richard Cochran <richardcochran@gmail.com>
To: Harini Katakam <harini.katakam@xilinx.com>
Cc: nicolas.ferre@microchip.com, davem@davemloft.net,
claudiu.beznea@microchip.com, andrei.pistirica@microchip.com,
kuba@kernel.org, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org, michal.simek@xilinx.com,
harinikatakamlinux@gmail.com
Subject: Re: [RFC PATCH] net: macb: Process tx timestamp only on ptp packets
Date: Tue, 24 Aug 2021 07:05:42 -0700 [thread overview]
Message-ID: <20210824140542.GA17195@hoboy.vegasvil.org> (raw)
In-Reply-To: <20210824101238.21105-1-harini.katakam@xilinx.com>
On Tue, Aug 24, 2021 at 03:42:38PM +0530, Harini Katakam wrote:
> The current implementation timestamps all packets and also processes
> the BD timestamp for the same. While it is true that HWTSTAMP_TX_ON
> enables timestamps for outgoing packets, the sender of the packet
> i.e. linuxptp enables timestamp for PTP or PTP event packets. Cadence
> GEM IP has a provision to enable this in HW only for PTP packets.
> Enable this option in DMA BD settings register to decrease overhead.
NAK, because the HWTSTAMP_TX_ON means to time stamp any frame marked
by user space, not just PTP frames.
This patch does not "decrease overhead" because the code tests whether
time stamping was request per packet:
drivers/net/ethernet/cadence/macb_main.c line 1202
if (unlikely(skb_shinfo(skb)->tx_flags &
SKBTX_HW_TSTAMP) &&
gem_ptp_do_txstamp(queue, skb, desc) == 0) {
...
}
Thanks,
Richard
next prev parent reply other threads:[~2021-08-24 14:05 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-24 10:12 [RFC PATCH] net: macb: Process tx timestamp only on ptp packets Harini Katakam
2021-08-24 14:05 ` Richard Cochran [this message]
2021-08-24 15:29 ` Harini Katakam
2021-08-25 2:08 ` Richard Cochran
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