Messages in this thread | | | Subject | Re: stmmac ethernet in kernel 4.4: coalescing related pauses? | From | Lino Sanfilippo <> | Date | Mon, 28 Nov 2016 16:57:35 +0100 |
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On 28.11.2016 16:31, Eric Dumazet wrote: > On Mon, 2016-11-28 at 09:54 -0500, David Miller wrote: >> From: Lino Sanfilippo <lsanfil@marvell.com> >> Date: Mon, 28 Nov 2016 14:07:51 +0100 >> >>> Calling skb_orphan() in the xmit handler made this issue disappear. >> >> This is not the way to handle this problem. >> >> The solution is to free the SKBs in a timely manner after the >> chip has transmitted the frame. > > Note that the 'pauses' described by Pavel are also caused by a too small > SO_SNDBUF value on the UDP socket. > > An immediate fix, with no kernel change is to increase it. > > echo 1000000 >/proc/sys/net/core/wmem_default > > or > > val = 1000000; > setsockopt(fd, SOL_SOCKET, SO_SNDBUF, &val, sizeof(val)); >
I wonder if the best fix would be indeed to deactivate irq coalescing completely. Does it make any sense at all to use it if a driver uses NAPI already?
Regards, Lino
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