From 398c2b05bbee21cc172dfff017c0351d4d14e04c Mon Sep 17 00:00:00 2001
From: Yamin Friedman <yaminf@mellanox.com>
Date: Thu, 22 Nov 2018 09:51:17 +0200
Subject: [PATCH] linux/dim: Add completions count to dim_sample

Added a measurement of completions per/msec to allow for completion based
dim algorithms.

In order to use dynamic interrupt moderation with RDMA we need to have a
different measurment than packets per second. This change is meant to
prepare for adding a new DIM method.

All drivers that use net_dim and thus do not need a completion count will
have the completions set to 0.

Signed-off-by: Yamin Friedman <yaminf@mellanox.com>
Reviewed-by: Max Gurtovoy <maxg@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
---
 include/linux/dim.h | 28 +++++++++++++++++++++++++---
 lib/dim/dim.c       |  9 +++++++++
 2 files changed, 34 insertions(+), 3 deletions(-)

diff --git a/include/linux/dim.h b/include/linux/dim.h
index f48ede3e0322..aa9bdd47a648 100644
--- a/include/linux/dim.h
+++ b/include/linux/dim.h
@@ -37,6 +37,7 @@
 struct dim_cq_moder {
 	u16 usec;
 	u16 pkts;
+	u16 comps;
 	u8 cq_period_mode;
 };
 
@@ -54,6 +55,7 @@ struct dim_sample {
 	u32 pkt_ctr;
 	u32 byte_ctr;
 	u16 event_ctr;
+	u32 comp_ctr;
 };
 
 /**
@@ -65,9 +67,11 @@ struct dim_sample {
  * @epms: Events per msec
  */
 struct dim_stats {
-	int ppms;
-	int bpms;
-	int epms;
+	int ppms; /* packets per msec */
+	int bpms; /* bytes per msec */
+	int epms; /* events per msec */
+	int cpms; /* completions per msec */
+	int cpe_ratio; /* ratio of completions to events */
 };
 
 /**
@@ -89,6 +93,7 @@ struct dim {
 	u8 state;
 	struct dim_stats prev_stats;
 	struct dim_sample start_sample;
+	struct dim_sample measuring_sample;
 	struct work_struct work;
 	u8 profile_ix;
 	u8 mode;
@@ -246,6 +251,23 @@ dim_update_sample(u16 event_ctr, u64 packets, u64 bytes, struct dim_sample *s)
 	s->event_ctr = event_ctr;
 }
 
+/**
+ *	dim_update_sample_with_comps - set a sample's fields with given
+ *	values including the completion parameter
+ *	@event_ctr: number of events to set
+ *	@packets: number of packets to set
+ *	@bytes: number of bytes to set
+ *	@comps: number of completions to set
+ *	@s: DIM sample
+ */
+static inline void
+dim_update_sample_with_comps(u16 event_ctr, u64 packets, u64 bytes, u64 comps,
+			     struct dim_sample *s)
+{
+	dim_update_sample(event_ctr, packets, bytes, s);
+	s->comp_ctr = comps;
+}
+
 /* Net DIM */
 
 /*
diff --git a/lib/dim/dim.c b/lib/dim/dim.c
index 17d5236759bd..439d641ec796 100644
--- a/lib/dim/dim.c
+++ b/lib/dim/dim.c
@@ -62,6 +62,8 @@ void dim_calc_stats(struct dim_sample *start, struct dim_sample *end,
 	u32 npkts = BIT_GAP(BITS_PER_TYPE(u32), end->pkt_ctr, start->pkt_ctr);
 	u32 nbytes = BIT_GAP(BITS_PER_TYPE(u32), end->byte_ctr,
 			     start->byte_ctr);
+	u32 ncomps = BIT_GAP(BITS_PER_TYPE(u32), end->comp_ctr,
+			     start->comp_ctr);
 
 	if (!delta_us)
 		return;
@@ -70,5 +72,12 @@ void dim_calc_stats(struct dim_sample *start, struct dim_sample *end,
 	curr_stats->bpms = DIV_ROUND_UP(nbytes * USEC_PER_MSEC, delta_us);
 	curr_stats->epms = DIV_ROUND_UP(DIM_NEVENTS * USEC_PER_MSEC,
 					delta_us);
+	curr_stats->cpms = DIV_ROUND_UP(ncomps * USEC_PER_MSEC, delta_us);
+	if (curr_stats->epms != 0)
+		curr_stats->cpe_ratio =
+				(curr_stats->cpms * 100) / curr_stats->epms;
+	else
+		curr_stats->cpe_ratio = 0;
+
 }
 EXPORT_SYMBOL(dim_calc_stats);