ice: fix software generating extra interrupts

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The driver tried to work around missing completion events that occurred
while interrupts are disabled, by triggering a software interrupt
whenever we exit polling (but we had to have polled at least once).

This was causing a *lot* of extra interrupts for some workloads like
NVMe over TCP, which resulted in regressions in performance. It was also
visible when polling didn't prevent interrupts when busy_poll was
enabled.

Fix the extra interrupts by utilizing our previously unused 3rd ITR
(interrupt throttle) index and set it to 20K interrupts per second, and
then trigger a software interrupt within that rate limit.

While here, slightly refactor the code to avoid an overwrite of a local
variable in the case of wb_en = true.

Fixes: b7306b42be ("ice: manage interrupts during poll exit")
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: Gurucharan G <gurucharanx.g@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

...

This commit is contained in:

Jesse Brandeburg 2021-09-20 12:30:14 -07:00 • committed by Tony Nguyen

parent d16a4f45f3

commit 23be7075b3

2 changed files with 16 additions and 11 deletions

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1

drivers/net/ethernet/intel/ice/ice_hw_autogen.h

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26

drivers/net/ethernet/intel/ice/ice_txrx.c

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