Re: [Intel-wired-lan] [PATCH v1 1/1] igc: enable multiple TXSTMP registers reporting TX timestamp.

[Paul Menzel]

[Resent with corrected address linux-kernel@ from original mail]

Am 24.04.23 um 21:01 schrieb Paul Menzel:
> Dear  Xiao Yan,
>
>
> Am 23.04.23 um 09:53 schrieb gongxiao-intel:
>
> Your name is incorrectly configured. Please do (please correct the 
> spelling):
>
>      $ git config --global user.name "Xiao Yan Gong"
>      $ git commit --amend -s --author="Xiao Yan Gong <xiaoyan.gong@xxxxxxxxx>"
>
> Also, please remove the dot/period from the end of the commit message 
> summary.
>
> > The HW TX timestamps created by the NIC via socket options can be
> > requested using the current network timestamps generation capability of
> > SOF_TIMESTAMPING_TX_HARDWARE. The most common users of this socket flag
> > is PTP, however other packet applications that require tx timestamps might
> > also ask for it.
> >
> > The problem is that, when there is a lot of traffic, there is a high chance
> > that the timestamps for a PTP packet will be lost if both PTP and Non-PTP
>
> non-PTP
>
> > packets use the same SOF_TIMESTAMPING_TX_HARDWARE causing the tx timeout.
>
> Is Linux logging this? If so, please paste such a message.
>
> > The root cause of this problem is that igc only use one TXSTMP 
> > register to
>
> use*s*
>
> > report TX timestamp. Such implementation intensify the race of TX 
> > timestamp
>
> intensif*ies*
>
> > query from multiple sockets.
> >
> > However, Intel i225/i226 controller has 4 TXSTMP registers. This patch fully
> > utilizes 4 TXSTMP registers to reduce the race of TX timestamp query.
> >
> > This patch dedicates TXSTMP register 0 to all PTP packets. In most case, only
> > one PTP sync process will run on a network port. So, one TXSTMP register is
> > enough for PTP stream.
> >
> > For TXSTMP register 1 - 3, they are allocated to sockets round robin. 
> > And each
>
> register*s*
>
> > socket can only occupy one register at a time. So, at least 3 sockets 
> > can requiest
>
> request
>
> > TX timestamp simultaneously.
>
> Please add Signed-off-by line.
>
> How did you test your patch?
>
> > ---
> >   drivers/net/ethernet/intel/igc/igc.h         | 24 +++--
> >   drivers/net/ethernet/intel/igc/igc_base.h    |  2 +-
> >   drivers/net/ethernet/intel/igc/igc_defines.h |  2 +-
> >   drivers/net/ethernet/intel/igc/igc_main.c    | 55 +++++++++--
> >   drivers/net/ethernet/intel/igc/igc_ptp.c     | 97 +++++++++++++-------
> >   drivers/net/ethernet/intel/igc/igc_regs.h    |  4 +-
> >   6 files changed, 129 insertions(+), 55 deletions(-)
>
> […]
>
>
> Kind regards,
>
> Paul