Re: [PATCH net-next] net: lan966x: Improve the CPU TX bitrate.

Jakub Kicinski
2022-03-09T01:02:10Z

On Tue, 8 Mar 2022 23:30:00 +0100 Horatiu Vultur wrote:
> > > static int lan966x_port_inj_ready(struct lan966x *lan966x, u8 grp)
> > > {
> > > - u32 val;
> > > + unsigned long time = jiffies + usecs_to_jiffies(READL_TIMEOUT_US);
> > > + int ret = 0;
> > >
> > > - return readx_poll_timeout_atomic(lan966x_port_inj_status, lan966x, val,
> > > - QS_INJ_STATUS_FIFO_RDY_GET(val) & BIT(grp),
> > > - READL_SLEEP_US, READL_TIMEOUT_US);
> > > + while (!(lan_rd(lan966x, QS_INJ_STATUS) &
> > > + QS_INJ_STATUS_FIFO_RDY_SET(BIT(grp)))) {
> > > + if (time_after(jiffies, time)) {
> > > + ret = -ETIMEDOUT;
> > > + break;
> > > + }
> >
> > Did you try setting READL_SLEEP_US to 0? readx_poll_timeout_atomic()
> > explicitly supports that.
>
> I have tried but it didn't improve. It was the same as before.

Huh, is ktime_get() super expensive on that platform?
jiffies vs ktime seems to be the main difference?