Messages in this thread | | | From | Ilya Lipnitskiy <> | Date | Thu, 22 Apr 2021 21:16:19 -0700 | Subject | Re: [PATCH net-next 05/14] net: ethernet: mtk_eth_soc: reduce MDIO bus access latency |
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On Thu, Apr 22, 2021 at 5:33 AM Felix Fietkau <nbd@nbd.name> wrote: > > > On 2021-04-22 06:09, Ilya Lipnitskiy wrote: > > From: Felix Fietkau <nbd@nbd.name> > > > > usleep_range often ends up sleeping much longer than the 10-20us provided > > as a range here. This causes significant latency in mdio bus acceses, > > which easily adds multiple seconds to the boot time on MT7621 when polling > > DSA slave ports. > > > > Use udelay via readx_poll_timeout_atomic, since the MDIO access does not > > take much time > > > > Signed-off-by: Felix Fietkau <nbd@nbd.name> > > [Ilya: use readx_poll_timeout_atomic instead of cond_resched] > I still prefer the cond_resched() variant. No problem, I will respin with your original change. Looks like we can't take advantage of iopoll.h routine in this case, but that's not the end of the world!
> On a fully loaded system, I'd > prefer to let the MDIO access take longer instead of wasting cycles on > udelay. > > - Felix
Ilya
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