Re: [PATCH 3/4] net: stmmac: modify default value of tx-frames

[Andrew Lunn]

On Thu, May 30, 2019 at 04:54:43PM +0800, Biao Huang wrote:
> the default value of tx-frames is 25, it's too late when
> passing tstamp to stack, then the ptp4l will fail:
> 
> ptp4l -i eth0 -f gPTP.cfg -m
> ptp4l: selected /dev/ptp0 as PTP clock
> ptp4l: port 1: INITIALIZING to LISTENING on INITIALIZE
> ptp4l: port 0: INITIALIZING to LISTENING on INITIALIZE
> ptp4l: port 1: link up
> ptp4l: timed out while polling for tx timestamp
> ptp4l: increasing tx_timestamp_timeout may correct this issue,
>        but it is likely caused by a driver bug
> ptp4l: port 1: send peer delay response failed
> ptp4l: port 1: LISTENING to FAULTY on FAULT_DETECTED (FT_UNSPECIFIED)
> 
> ptp4l tests pass when changing the tx-frames from 25 to 1 with
> ethtool -C option.
> It should be fine to set tx-frames default value to 1, so ptp4l will pass
> by default.

Hi Biao

What does this do to the number of interrupts? Do we get 25 times more
interrupts? Have you done any performance tests to see if this causes
performance regressions?

	    Andrew