linuxptp-users

[Linuxptp-users] unabel to start ptp4l service in centos 7.4

[Raveendra M. <rav...@gm...>]

I am using following kernel version in development machine

3.10.0-rt56 #2 SMP PREEMPT RT Tue May 22 08:44:25 EDT 2018 x86_64 x86_64
x86_64 GNU/Linux


Hardware capbility of ethernet nic card

[root@2-9 ~]# ethtool -T eth0
Time stamping parameters for eth0:
Capabilities:
software-receive      (SOF_TIMESTAMPING_RX_SOFTWARE)
software-system-clock (SOF_TIMESTAMPING_SOFTWARE)
PTP Hardware Clock: none
Hardware Transmit Timestamp Modes: none
Hardware Receive Filter Modes: none
[root@2-9 ~]#

After installing started the ptp4l service

[root@2-9 ~]# systemctl start ptp4l
[root@2-9 ~]# systemctl status ptp4l
â— ptp4l.service - Precision Time Protocol (PTP) service
   Loaded: loaded (/usr/lib/systemd/system/ptp4l.service; disabled; vendor
preset: disabled)
   Active: failed (Result: exit-code) since Wed 2019-03-13 17:56:17 IST; 5s
ago
  Process: 8939 ExecStart=/usr/sbin/ptp4l $OPTIONS (code=exited, status=255)
 Main PID: 8939 (code=exited, status=255)

Syslog captured following log

Mar 13 17:56:17 2-9.mavenir1.com systemd[1]: Started Precision Time
Protocol (PTP) service.
Mar 13 17:56:17 2-9.mavenir1.com systemd[1]: Starting Precision Time
Protocol (PTP) service...
Mar 13 17:56:17 2-9.mavenir1.com ptp4l[8939]: failed to create a clock
Mar 13 17:56:17 2-9.mavenir1.com systemd[1]: ptp4l.service: main process
exited, code=exited, status=255/n/a
Mar 13 17:56:17 2-9.mavenir1.com systemd[1]: Unit ptp4l.service entered
failed state.
Mar 13 17:56:17 2-9.mavenir1.com systemd[1]: ptp4l.service failed.


ar 13 17:54:16 2-9 systemd: Starting Session 2998 of user root.
Mar 13 17:55:05 2-9 systemd: Reloading.
Mar 13 17:55:05 2-9 kernel: hrtimer: interrupt took 10571539 ns
Mar 13 17:56:17 2-9 systemd: Started Precision Time Protocol (PTP) service.
Mar 13 17:56:17 2-9 systemd: Starting Precision Time Protocol (PTP)
service...
Mar 13 17:56:17 2-9 ptp4l: [1397593.140] interface 'eth0' does not support
requested timestamping mode
Mar 13 17:56:17 2-9 ptp4l: failed to create a clock
Mar 13 17:56:17 2-9 systemd: ptp4l.service: main process exited,
code=exited, status=255/n/a
Mar 13 17:56:17 2-9 systemd: Unit ptp4l.service entered failed state.
Mar 13 17:56:17 2-9 systemd: ptp4l.service failed.



Any suggestion how ptp4l service can be started and also use software based
timestamping for ptp protocol.

Thanking you,
Raveendra M

Re: [Linuxptp-users] unabel to start ptp4l service in centos 7.4

[Miroslav L. <mli...@re...>]

On Wed, Mar 13, 2019 at 06:19:34PM +0530, Raveendra Muniyappa wrote:
> [root@2-9 ~]# ethtool -T eth0
> Time stamping parameters for eth0:
> Capabilities:
> software-receive      (SOF_TIMESTAMPING_RX_SOFTWARE)
> software-system-clock (SOF_TIMESTAMPING_SOFTWARE)

> Mar 13 17:56:17 2-9 ptp4l: [1397593.140] interface 'eth0' does not support
> requested timestamping mode

> Any suggestion how ptp4l service can be started and also use software based
> timestamping for ptp protocol.

ptp4l cannot be started on this interface. It requires the
SOF_TIMESTAMPING_TX_SOFTWARE capability, which is not printed by
ethtool.

-- 
Miroslav Lichvar

Re: [Linuxptp-users] unabel to start ptp4l service in centos 7.4

[Raveendra M. <rav...@gm...>]

I found some information regarding SOF_TIMESTAMPING_TX_SOFTWARE capability


https://sourceforge.net/p/linuxptp/mailman/message/35474590/


You need to add one line to the transmit path in the driver:

	skb_tx_timestamp(skb);

Quoting include/linux/skbuff.h:

 * skb_tx_timestamp() - Driver hook for transmit timestamping
 *
 * Ethernet MAC Drivers should call this function in their hard_xmit()
 * function immediately before giving the sk_buff to the MAC hardware.
 *
 * Specifically, one should make absolutely sure that this function is
 * called before TX completion of this packet can trigger.  Otherwise
 * the packet could potentially already be freed.

if I modify the nic driver with above changes then will ptp4l able to
start the ptp service ?

Regards,

Raveendra






On Wed, Mar 13, 2019 at 6:25 PM Miroslav Lichvar <mli...@re...>
wrote:

> On Wed, Mar 13, 2019 at 06:19:34PM +0530, Raveendra Muniyappa wrote:
> > [root@2-9 ~]# ethtool -T eth0
> > Time stamping parameters for eth0:
> > Capabilities:
> > software-receive      (SOF_TIMESTAMPING_RX_SOFTWARE)
> > software-system-clock (SOF_TIMESTAMPING_SOFTWARE)
>
> > Mar 13 17:56:17 2-9 ptp4l: [1397593.140] interface 'eth0' does not
> support
> > requested timestamping mode
>
> > Any suggestion how ptp4l service can be started and also use software
> based
> > timestamping for ptp protocol.
>
> ptp4l cannot be started on this interface. It requires the
> SOF_TIMESTAMPING_TX_SOFTWARE capability, which is not printed by
> ethtool.
>
> --
> Miroslav Lichvar
>

Re: [Linuxptp-users] unabel to start ptp4l service in centos 7.4

[Miroslav L. <mli...@re...>]

On Wed, Mar 13, 2019 at 06:47:56PM +0530, Raveendra Muniyappa wrote:
> I found some information regarding SOF_TIMESTAMPING_TX_SOFTWARE capability
> 
> 
> https://sourceforge.net/p/linuxptp/mailman/message/35474590/
> 
> 
> You need to add one line to the transmit path in the driver:
> 
> 	skb_tx_timestamp(skb);

> if I modify the nic driver with above changes then will ptp4l able to
> start the ptp service ?

Yes.

I'd suggest to look at the current Linux code. It's likely the driver
already has this call and you would just backport that change to your
kernel.

-- 
Miroslav Lichvar