Add two new counters to struct dql that are num_enqueue_ops and
num_completed_ops. num_enqueue_ops is incremented by one in each call to
dql_queued. num_enqueue_ops is incremented in dql_completed which takes
an argument indicating number of operations completed. These counters
are only intended for statistics and do not impact the BQL algorithm.
We add a new sysfs entry in byte_queue_limits named inflight_pkts.
This provides the number of packets in flight for the queue by
dql->num_enqueue_ops - dql->num_completed_ops.
Signed-off-by: Tom Herbert <t...@herbertland.com>
---
include/linux/dynamic_queue_limits.h | 7 ++++++-
include/linux/netdevice.h | 2 +-
lib/dynamic_queue_limits.c | 3 ++-
net/core/net-sysfs.c | 14 ++++++++++++++
4 files changed, 23 insertions(+), 3 deletions(-)
diff --git a/include/linux/dynamic_queue_limits.h
b/include/linux/dynamic_queue_limits.h
index a4be703..b6a4804 100644
--- a/include/linux/dynamic_queue_limits.h
+++ b/include/linux/dynamic_queue_limits.h
@@ -43,6 +43,8 @@ struct dql {
unsigned int adj_limit; /* limit + num_completed */
unsigned int last_obj_cnt; /* Count at last queuing */
+ unsigned int num_enqueue_ops; /* Number of queue operations */
+
/* Fields accessed only by completion path (dql_completed) */
unsigned int limit ____cacheline_aligned_in_smp; /* Current limit */
@@ -55,6 +57,8 @@ struct dql {
unsigned int lowest_slack; /* Lowest slack found */
unsigned long slack_start_time; /* Time slacks seen */
+ unsigned int num_completed_ops; /* Number of complete ops */
+
/* Configuration */
unsigned int max_limit; /* Max limit */
unsigned int min_limit; /* Minimum limit */
@@ -83,6 +87,7 @@ static inline void dql_queued(struct dql *dql, unsigned int
count)
barrier();
dql->num_queued += count;
+ dql->num_enqueue_ops++;
}
/* Returns how many objects can be queued, < 0 indicates over limit. */
@@ -92,7 +97,7 @@ static inline int dql_avail(const struct dql *dql)
}
/* Record number of completed objects and recalculate the limit. */
-void dql_completed(struct dql *dql, unsigned int count);
+void dql_completed(struct dql *dql, unsigned int count, unsigned int ops);
/* Reset dql state */
void dql_reset(struct dql *dql);
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index d122be9..0d1d748 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2999,7 +2999,7 @@ static inline void netdev_tx_completed_queue(struct
netdev_queue *dev_queue,
if (unlikely(!bytes))
return;
- dql_completed(&dev_queue->dql, bytes);
+ dql_completed(&dev_queue->dql, bytes, pkts);
/*
* Without the memory barrier there is a small possiblity that
diff --git a/lib/dynamic_queue_limits.c b/lib/dynamic_queue_limits.c
index f346715..d5e7a27 100644
--- a/lib/dynamic_queue_limits.c
+++ b/lib/dynamic_queue_limits.c
@@ -14,7 +14,7 @@
#define AFTER_EQ(A, B) ((int)((A) - (B)) >= 0)
/* Records completed count and recalculates the queue limit */
-void dql_completed(struct dql *dql, unsigned int count)
+void dql_completed(struct dql *dql, unsigned int count, unsigned int ops)
{
unsigned int inprogress, prev_inprogress, limit;
unsigned int ovlimit, completed, num_queued;
@@ -108,6 +108,7 @@ void dql_completed(struct dql *dql, unsigned int count)
dql->prev_ovlimit = ovlimit;
dql->prev_last_obj_cnt = dql->last_obj_cnt;
dql->num_completed = completed;
+ dql->num_completed_ops += ops;
dql->prev_num_queued = num_queued;
}
EXPORT_SYMBOL(dql_completed);
diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index 6e4f347..ab7b0b6 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -1147,6 +1147,19 @@ static ssize_t bql_show_inflight(struct netdev_queue
*queue,
static struct netdev_queue_attribute bql_inflight_attribute =
__ATTR(inflight, S_IRUGO, bql_show_inflight, NULL);
+static ssize_t bql_show_inflight_pkts(struct netdev_queue *queue,
+ struct netdev_queue_attribute *attr,
+ char *buf)
+{
+ struct dql *dql = &queue->dql;
+
+ return sprintf(buf, "%u\n",
+ dql->num_enqueue_ops - dql->num_completed_ops);
+}
+
+static struct netdev_queue_attribute bql_inflight_pkts_attribute =
+ __ATTR(inflight_pkts, S_IRUGO, bql_show_inflight_pkts, NULL);
+
#define BQL_ATTR(NAME, FIELD) \
static ssize_t bql_show_ ## NAME(struct netdev_queue *queue, \
struct netdev_queue_attribute *attr, \
@@ -1176,6 +1189,7 @@ static struct attribute *dql_attrs[] = {
&bql_limit_min_attribute.attr,
&bql_hold_time_attribute.attr,
&bql_inflight_attribute.attr,
+ &bql_inflight_pkts_attribute.attr,
NULL
};
--
2.8.0.rc2
