8edc0e624d
This patch originated from Hiroaki SHIMODA but has been modified
by Intel with some minor cleanups and additional commit log text.
Denys Fedoryshchenko and others reported Tx stalls on e1000e with
BQL enabled. Issue was root caused to hardware delays. They were
introduced because some of the e1000e hardware with transmit
writeback bursting enabled, waits until the driver does an
explict flush OR there are WTHRESH descriptors to write back.
Sometimes the delays in question were on the order of seconds,
causing visible lag for ssh sessions and unacceptable tx
completion latency, especially for BQL enabled kernels.
To avoid possible Tx stalls, change WTHRESH back to 1.
The current plan is to investigate a method for re-enabling
WTHRESH while not harming BQL, but those patches will be later
for net-next if they work.
please enqueue for stable since v3.3 as this bug was introduced in
commit
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|---|---|---|
| .. | ||
| e1000 | ||
| e1000e | ||
| igb | ||
| igbvf | ||
| ixgb | ||
| ixgbe | ||
| ixgbevf | ||
| Kconfig | ||
| Makefile | ||
| e100.c | ||