linux-toradex.git/include/linux/net_dim.h, branch v5.1-rc4

net/dim: Update DIM start sample after each DIM iteration

2018-11-22T19:36:54+00:00

On every iteration of net_dim, the algorithm may choose to
check for the system state by comparing current data sample
with previous data sample. After each of these comparison,
regardless of the action taken, the sample used as baseline
is needed to be updated.

This patch fixes a bug that causes DIM to take wrong decisions,
due to never updating the baseline sample for comparison between
iterations. This way, DIM always compares current sample with
zeros.

Although this is a functional fix, it also improves and stabilizes
performance as the algorithm works properly now.

Performance:
Tested single UDP TX stream with pktgen:
samples/pktgen/pktgen_sample03_burst_single_flow.sh -i p4p2 -d 1.1.1.1
-m 24:8a:07:88:26:8b -f 3 -b 128

ConnectX-5 100GbE packet rate improved from 15-19Mpps to 19-20Mpps.
Also, toggling between profiles is less frequent with the fix.

Fixes: 8115b750dbcb ("net/dim: use struct net_dim_sample as arg to net_dim")
Signed-off-by: Tal Gilboa 
Reviewed-by: Tariq Toukan 
Signed-off-by: David S. Miller

include/linux/bitops.h: introduce BITS_PER_TYPE

2018-08-22T17:52:48+00:00

net_dim.h has a rather useful extension to BITS_PER_BYTE to compute the
number of bits in a type (BITS_PER_BYTE * sizeof(T)), so promote the macro
to bitops.h, alongside BITS_PER_BYTE, for wider usage.

Link: http://lkml.kernel.org/r/20180706094458.14116-1-chris@chris-wilson.co.uk
Signed-off-by: Chris Wilson 
Reviewed-by: Jani Nikula 
Cc: Randy Dunlap 
Cc: Andy Gospodarek 
Cc: David S. Miller 
Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

net/dim: Support adaptive TX moderation

2018-04-24T14:15:07+00:00

Interrupt moderation for TX traffic requires different profiles than RX
interrupt moderation. The main goal here is to reduce interrupt rate and
allow better payload aggregation by keeping SKBs in the TX queue a bit
longer. Ping-pong behavior would get a profile with a short timer, so
latency wouldn't increase for these scenarios. There might be a slight
degradation in bandwidth for single stream with large message sizes, since
net.ipv4.tcp_limit_output_bytes is limiting the allowed TX traffic, but
with many streams performance is always improved.

Signed-off-by: Tal Gilboa 
Reviewed-by: Tariq Toukan 
Signed-off-by: David S. Miller

net/dim: Rename _get_profile() functions to _get_rx_moderation()

2018-04-24T14:15:07+00:00

Preparation for introducing adaptive TX to net DIM.

Signed-off-by: Tal Gilboa 
Reviewed-by: Tariq Toukan 
Signed-off-by: David S. Miller

net/dim: Fix int overflow

2018-03-30T16:56:22+00:00

When calculating difference between samples, the values
are multiplied by 100. Large values may cause int overflow
when multiplied (usually on first iteration).
Fixed by forcing 100 to be of type unsigned long.

Fixes: 4c4dbb4a7363 ("net/mlx5e: Move dynamic interrupt coalescing code to include/linux")
Signed-off-by: Tal Gilboa 
Reviewed-by: Andy Gospodarek 
Signed-off-by: David S. Miller

net/dim: Fix fixpoint divide exception in net_dim_stats_compare

2018-01-19T19:53:32+00:00

Helmut reported a bug about devision by zero while
running traffic and doing physical cable pull test.

When the cable unplugged the ppms become zero, so when
dividing the current ppms by the previous ppms in the
next dim iteration there is devision by zero.

This patch prevent this division for both ppms and epms.

Fixes: c3164d2fc48f ("net/mlx5e: Added BW check for DIM decision mechanism")
Fixes: 4c4dbb4a7363 ("net/mlx5e: Move dynamic interrupt coalescing code to include/linux")
Reported-by: Helmut Grauer 
Signed-off-by: Talat Batheesh 
Signed-off-by: Tal Gilboa 
Signed-off-by: David S. Miller

net/dim: use struct net_dim_sample as arg to net_dim

2018-01-10T20:27:45+00:00

Simplify the arguments net_dim() by formatting them into a struct
net_dim_sample before calling the function.

Signed-off-by: Andy Gospodarek 
Suggested-by: Tal Gilboa 
Acked-by: Tal Gilboa 
Acked-by: Saeed Mahameed 
Signed-off-by: David S. Miller

net/mlx5e: Move dynamic interrupt coalescing code to include/linux

2018-01-10T20:27:44+00:00

This move allows drivers to add private structure elements to track the
number of packets, bytes, and interrupts events per ring.  A driver
also defines a workqueue handler to act on this collected data once per
poll and modify the coalescing parameters per ring.

Signed-off-by: Andy Gospodarek 
Acked-by: Tal Gilboa 
Acked-by: Saeed Mahameed 
Signed-off-by: David S. Miller