Ocelot loops over memory regions to gather stats on different ports.
These regions are mostly continuous, and are ordered. This patch set
uses that information to break the stats reads into regions that can get
read in bulk.
The motiviation is for general cleanup, but also for SPI. Performing two
back-to-back reads on a SPI bus require toggling the CS line, holding,
re-toggling the CS line, sending 3 address bytes, sending N padding
bytes, then actually performing the read. Bulk reads could reduce almost
all of that overhead, but require that the reads are performed via
regmap_bulk_read.
Verified with eth0 hooked up to the CPU port:
# ethtool -S eth0 | grep -v ": 0"
NIC statistics:
Good Rx Frames: 905
Rx Octets: 78848
Good Tx Frames: 691
Tx Octets: 52516
Rx + Tx 65-127 Octet Frames: 1574
Rx + Tx 128-255 Octet Frames: 22
Net Octets: 131364
Rx DMA chan 0: head_enqueue: 1
Rx DMA chan 0: tail_enqueue: 1032
Rx DMA chan 0: busy_dequeue: 628
Rx DMA chan 0: good_dequeue: 905
Tx DMA chan 0: head_enqueue: 346
Tx DMA chan 0: tail_enqueue: 345
Tx DMA chan 0: misqueued: 345
Tx DMA chan 0: empty_dequeue: 346
Tx DMA chan 0: good_dequeue: 691
p00_rx_octets: 52516
p00_rx_unicast: 691
p00_rx_frames_65_to_127_octets: 691
p00_tx_octets: 78848
p00_tx_unicast: 905
p00_tx_frames_65_to_127_octets: 883
p00_tx_frames_128_255_octets: 22
p00_tx_green_prio_0: 905
And with swp2 connected to swp3 with STP enabled:
# ethtool -S swp2 | grep -v ": 0"
NIC statistics:
tx_packets: 379
tx_bytes: 19708
rx_packets: 1
rx_bytes: 46
rx_octets: 64
rx_multicast: 1
rx_frames_below_65_octets: 1
rx_classified_drops: 1
tx_octets: 44630
tx_multicast: 387
tx_broadcast: 290
tx_frames_below_65_octets: 379
tx_frames_65_to_127_octets: 294
tx_frames_128_255_octets: 4
tx_green_prio_0: 298
tx_green_prio_7: 379
# ethtool -S swp3 | grep -v ": 0"
NIC statistics:
tx_packets: 1
tx_bytes: 52
rx_packets: 713
rx_bytes: 34148
rx_octets: 46982
rx_multicast: 407
rx_broadcast: 306
rx_frames_below_65_octets: 399
rx_frames_65_to_127_octets: 310
rx_frames_128_to_255_octets: 4
rx_classified_drops: 399
rx_green_prio_0: 314
tx_octets: 64
tx_multicast: 1
tx_frames_below_65_octets: 1
tx_green_prio_7: 1
v1 > v2: reword commit messages
v2 > v3: correctly mark this for net-next when sending
v3 > v4: calloc array instead of zalloc per review
v4 > v5:
Apply CR suggestions for whitespace
Fix calloc / zalloc mixup
Properly destroy workqueues
Add third commit to split long macros
v5 > v6:
Fix functionality - v5 was improperly tested
Add bugfix for ethtool mutex lock
Remove unnecessary ethtool stats reads
v6 > v7:
Remove mutex bug patch that was applied via net
Rename function based on CR
Add missed error check
Colin Foster (4):
net: mscc: ocelot: remove unnecessary stat reading from ethtool
net: ocelot: align macros for consistency
net: mscc: ocelot: add ability to perform bulk reads
net: mscc: ocelot: use bulk reads for stats
drivers/net/ethernet/mscc/ocelot.c | 95 ++++++++++++++++++++++-----
drivers/net/ethernet/mscc/ocelot_io.c | 13 ++++
include/soc/mscc/ocelot.h | 57 +++++++++++-----
3 files changed, 133 insertions(+), 32 deletions(-)
--
2.25.1