[net-next,v3,0/6] Add adaptive interrupt coalescing

Apart from some related cleanup patches, this set
introduces in a straightforward way the support needed
to enable and configure interrupt coalescing for ENETC.

Patch 5 introduces the support needed for configuring the
interrupt coalescing parameters and for switching between
moderated (int. coalescing) and per-packet interrupt modes.
When interrupt coalescing is enabled the Rx/Tx time
thresholds are configurable, packet thresholds are fixed.
To make this work reliably, patch 5 uses the traffic
pause procedure introduced in patch 2.

Patch 6 adds DIM (Dynamic Interrupt Moderation) to implement
adaptive coalescing based on time thresholds, for the Rx 'channel'.
On the Tx side a default optimal value is used instead, optimized for
TCP traffic over 1G and 2.5G links.  This default 'optimal' value can
be overridden anytime via 'ethtool -C tx-usecs'.

netperf -t TCP_MAERTS measurements show a significant CPU load
reduction correlated w/ reduced interrupt rates. For the
measurement results refer to the comments in patch 6.

v2: Replaced Tx DIM with predefined optimal value, giving
better results. This was also suggested by Jakub (cc).
Switched order of patches 4 and 5, for better grouping.

v3: minor cleanup/improvements

Claudiu Manoil (6):
  enetc: Refine buffer descriptor ring sizes
  enetc: Factor out the traffic start/stop procedures
  enetc: Fix interrupt coalescing register naming
  enetc: Drop redundant ____cacheline_aligned_in_smp
  enetc: Add interrupt coalescing support
  enetc: Add adaptive interrupt coalescing

 drivers/net/ethernet/freescale/enetc/Kconfig  |   2 +
 drivers/net/ethernet/freescale/enetc/enetc.c  | 156 ++++++++++++++----
 drivers/net/ethernet/freescale/enetc/enetc.h  |  36 +++-
 .../ethernet/freescale/enetc/enetc_ethtool.c  |  84 +++++++++-
 .../net/ethernet/freescale/enetc/enetc_hw.h   |  23 ++-
 5 files changed, 257 insertions(+), 44 deletions(-)

On Tue, 21 Jul 2020 10:55:16 +0300 Claudiu Manoil wrote:
> Apart from some related cleanup patches, this set
> introduces in a straightforward way the support needed
> to enable and configure interrupt coalescing for ENETC.
> 
> Patch 5 introduces the support needed for configuring the
> interrupt coalescing parameters and for switching between
> moderated (int. coalescing) and per-packet interrupt modes.
> When interrupt coalescing is enabled the Rx/Tx time
> thresholds are configurable, packet thresholds are fixed.
> To make this work reliably, patch 5 uses the traffic
> pause procedure introduced in patch 2.
> 
> Patch 6 adds DIM (Dynamic Interrupt Moderation) to implement
> adaptive coalescing based on time thresholds, for the Rx 'channel'.
> On the Tx side a default optimal value is used instead, optimized for
> TCP traffic over 1G and 2.5G links.  This default 'optimal' value can
> be overridden anytime via 'ethtool -C tx-usecs'.
> 
> netperf -t TCP_MAERTS measurements show a significant CPU load
> reduction correlated w/ reduced interrupt rates. For the
> measurement results refer to the comments in patch 6.
> 
> v2: Replaced Tx DIM with predefined optimal value, giving
> better results. This was also suggested by Jakub (cc).
> Switched order of patches 4 and 5, for better grouping.

Acked-by: Jakub Kicinski <kuba@kernel.org>

From: Claudiu Manoil <claudiu.manoil@nxp.com>
Date: Tue, 21 Jul 2020 10:55:16 +0300

> Apart from some related cleanup patches, this set
> introduces in a straightforward way the support needed
> to enable and configure interrupt coalescing for ENETC.
> 
> Patch 5 introduces the support needed for configuring the
> interrupt coalescing parameters and for switching between
> moderated (int. coalescing) and per-packet interrupt modes.
> When interrupt coalescing is enabled the Rx/Tx time
> thresholds are configurable, packet thresholds are fixed.
> To make this work reliably, patch 5 uses the traffic
> pause procedure introduced in patch 2.
> 
> Patch 6 adds DIM (Dynamic Interrupt Moderation) to implement
> adaptive coalescing based on time thresholds, for the Rx 'channel'.
> On the Tx side a default optimal value is used instead, optimized for
> TCP traffic over 1G and 2.5G links.  This default 'optimal' value can
> be overridden anytime via 'ethtool -C tx-usecs'.
> 
> netperf -t TCP_MAERTS measurements show a significant CPU load
> reduction correlated w/ reduced interrupt rates. For the
> measurement results refer to the comments in patch 6.
> 
> v2: Replaced Tx DIM with predefined optimal value, giving
> better results. This was also suggested by Jakub (cc).
> Switched order of patches 4 and 5, for better grouping.
> 
> v3: minor cleanup/improvements

Series applied, thank you.