@@ -14,42 +14,74 @@
#define DQCOUNT_INVALID -1
#define PIE_SCALE 8
-/* parameters used */
+/**
+ * struct pie_params - contains pie parameters
+ * @target: target delay in pschedtime
+ * @tudpate: interval at which drop probability is calculated
+ * @limit: total number of packets that can be in the queue
+ * @alpha: parameter to control drop probability
+ * @beta: parameter to control drop probability
+ * @ecn: is ECN marking of packets enabled
+ * @bytemode: is drop probability scaled based on pkt size
+ * @dq_rate_estimator: is Little's law used for qdelay calculation
+ */
struct pie_params {
- psched_time_t target; /* user specified target delay in pschedtime */
- u32 tupdate; /* timer frequency (in jiffies) */
- u32 limit; /* number of packets that can be enqueued */
- u32 alpha; /* alpha and beta are between 0 and 32 */
- u32 beta; /* and are used for shift relative to 1 */
- u8 ecn; /* true if ecn is enabled */
- u8 bytemode; /* to scale drop early prob based on pkt size */
- u8 dq_rate_estimator; /* to calculate delay using Little's law */
+ psched_time_t target;
+ u32 tupdate;
+ u32 limit;
+ u32 alpha;
+ u32 beta;
+ u8 ecn;
+ u8 bytemode;
+ u8 dq_rate_estimator;
};
-/* variables used */
+/**
+ * struct pie_vars - contains pie variables
+ * @burst_time: burst time allowance
+ * @qdelay: current queue delay
+ * @qdelay_old: queue delay in previous qdelay calculation
+ * @dq_tstamp: timestamp at which dq rate was last calculated
+ * @prob: drop probability
+ * @accu_prob: accumulated drop probability
+ * @dq_count: number of bytes dequeued in a measurement cycle
+ * @avg_dq_rate: calculated average dq rate
+ * @qlen_old: queue length during previous qdelay calculation
+ * @accu_prob_overflow: number of times accu_prob overflows
+ */
struct pie_vars {
psched_time_t burst_time;
psched_time_t qdelay;
psched_time_t qdelay_old;
- psched_time_t dq_tstamp; /* drain rate */
- u64 prob; /* probability but scaled by u64 limit. */
- u64 accu_prob; /* accumulated drop probability */
- u64 dq_count; /* measured in bytes */
- u32 avg_dq_rate; /* bytes per pschedtime tick,scaled */
- u32 qlen_old; /* in bytes */
- u8 accu_prob_overflows; /* overflows of accu_prob */
+ psched_time_t dq_tstamp;
+ u64 prob;
+ u64 accu_prob;
+ u64 dq_count;
+ u32 avg_dq_rate;
+ u32 qlen_old;
+ u8 accu_prob_overflows;
};
-/* statistics gathering */
+/**
+ * struct pie_stats - contains pie stats
+ * @packets_in: total number of packets enqueued
+ * @dropped: packets dropped due to pie action
+ * @overlimit: packets dropped due to lack of space in queue
+ * @maxq: maximum queue size
+ * @ecn_mark: packets marked with ECN
+ */
struct pie_stats {
- u32 packets_in; /* total number of packets enqueued */
- u32 dropped; /* packets dropped due to pie_action */
- u32 overlimit; /* dropped due to lack of space in queue */
- u32 maxq; /* maximum queue size */
- u32 ecn_mark; /* packets marked with ECN */
+ u32 packets_in;
+ u32 dropped;
+ u32 overlimit;
+ u32 maxq;
+ u32 ecn_mark;
};
-/* private skb vars */
+/**
+ * struct pie_skb_cb - contains private skb vars
+ * @enqueue_time: timestamp when the packet is enqueued
+ */
struct pie_skb_cb {
psched_time_t enqueue_time;
};
@@ -58,7 +90,7 @@ static inline void pie_params_init(struct pie_params *params)
{
params->target = PSCHED_NS2TICKS(15 * NSEC_PER_MSEC); /* 15 ms */
params->tupdate = usecs_to_jiffies(15 * USEC_PER_MSEC); /* 15 ms */
- params->limit = 1000; /* default of 1000 packets */
+ params->limit = 1000;
params->alpha = 2;
params->beta = 20;
params->ecn = false;
@@ -68,8 +100,7 @@ static inline void pie_params_init(struct pie_params *params)
static inline void pie_vars_init(struct pie_vars *vars)
{
- /* default of 150 ms in pschedtime */
- vars->burst_time = PSCHED_NS2TICKS(150 * NSEC_PER_MSEC);
+ vars->burst_time = PSCHED_NS2TICKS(150 * NSEC_PER_MSEC); /* 150 ms */
vars->dq_tstamp = DTIME_INVALID;
vars->accu_prob = 0;
vars->dq_count = DQCOUNT_INVALID;