Re: [PATCH net-next 05/14] net: ethernet: mtk_eth_soc: reduce MDIO bus access latency
From: Felix Fietkau <nbd@nbd.name>
Date: 2021-04-22 12:33:47
Also in:
linux-arm-kernel, linux-mediatek, lkml
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. On a fully loaded system, I'd prefer to let the MDIO access take longer instead of wasting cycles on udelay. - Felix