Messages in this thread | | | Date | Wed, 9 Mar 2022 10:14:37 +0100 | From | Horatiu Vultur <> | Subject | Re: [PATCH net-next] net: lan966x: Improve the CPU TX bitrate. |
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The 03/08/2022 16:40, Jakub Kicinski wrote: > > 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?
Hm.. it looks like. Just adding ktime_get() before the while loop, then the performance drops like before. I am using SOC_LAN966 which has an ARMv7 CPU. So I am not sure how expensive is ktime_get().
> jiffies vs ktime seems to be the main difference?
-- /Horatiu
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