Re: [PATCH v3 5/5] latencystats: include file cleanup

[Bruce Richardson <bruce.richardson@intel.com>]

On Wed, Apr 17, 2024 at 10:07:27AM -0700, Stephen Hemminger wrote:
> Include what is used here.
> 
There are more changes in this patch than just includes cleanup.

> Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
> ---
>  lib/latencystats/rte_latencystats.c | 85 ++++++++++++++++++-----------
>  1 file changed, 52 insertions(+), 33 deletions(-)
> 
> diff --git a/lib/latencystats/rte_latencystats.c b/lib/latencystats/rte_latencystats.c
> index 62038a9f5d..31e7a6eb88 100644
> --- a/lib/latencystats/rte_latencystats.c
> +++ b/lib/latencystats/rte_latencystats.c
> @@ -2,16 +2,25 @@
>   * Copyright(c) 2018 Intel Corporation
>   */
>  
> +#include <errno.h>
>  #include <math.h>
> +#include <stdbool.h>
> +#include <stddef.h>
> +#include <string.h>
>  
> -#include <rte_string_fns.h>
> -#include <rte_mbuf_dyn.h>
> -#include <rte_log.h>
> +#include <rte_common.h>
>  #include <rte_cycles.h>
> +#include <rte_eal.h>
> +#include <rte_errno.h>
>  #include <rte_ethdev.h>
> -#include <rte_metrics.h>
> -#include <rte_memzone.h>
>  #include <rte_lcore.h>
> +#include <rte_log.h>
> +#include <rte_mbuf.h>
> +#include <rte_mbuf_dyn.h>
> +#include <rte_memzone.h>
> +#include <rte_metrics.h>
> +#include <rte_spinlock.h>
> +#include <rte_string_fns.h>
>  
>  #include "rte_latencystats.h"
>  
> @@ -148,14 +157,15 @@ add_time_stamps(uint16_t pid __rte_unused,
>  
>  static uint16_t
>  calc_latency(uint16_t pid __rte_unused,
> -		uint16_t qid __rte_unused,
> -		struct rte_mbuf **pkts,
> -		uint16_t nb_pkts,
> -		void *_ __rte_unused)
> +	     uint16_t qid __rte_unused,
> +	     struct rte_mbuf **pkts,
> +	     uint16_t nb_pkts,
> +	     void *_ __rte_unused)
>  {
>  	unsigned int i;
>  	uint64_t now, latency;
>  	static uint64_t prev_latency;
> +	static bool first_sample = true;
>  
>  	now = rte_rdtsc();
>  
> @@ -166,32 +176,41 @@ calc_latency(uint16_t pid __rte_unused,
>  
>  		latency = now - *timestamp_dynfield(pkts[i]);
>  
> -		/*
> -		 * The jitter is calculated as statistical mean of interpacket
> -		 * delay variation. The "jitter estimate" is computed by taking
> -		 * the absolute values of the ipdv sequence and applying an
> -		 * exponential filter with parameter 1/16 to generate the
> -		 * estimate. i.e J=J+(|D(i-1,i)|-J)/16. Where J is jitter,
> -		 * D(i-1,i) is difference in latency of two consecutive packets
> -		 * i-1 and i.
> -		 * Reference: Calculated as per RFC 5481, sec 4.1,
> -		 * RFC 3393 sec 4.5, RFC 1889 sec.
> -		 */
> -		glob_stats->jitter += ((prev_latency - latency) - glob_stats->jitter) / 16;
> -		if (glob_stats->min_latency == 0)
> -			glob_stats->min_latency = latency;
> -		else if (latency < glob_stats->min_latency)
> +		if (first_sample) {
> +			first_sample = false;
> +
>  			glob_stats->min_latency = latency;
> -		else if (latency > glob_stats->max_latency)
>  			glob_stats->max_latency = latency;
> -		/*
> -		 * The average latency is measured using exponential moving
> -		 * average, i.e. using EWMA
> -		 * https://en.wikipedia.org/wiki/Moving_average
> -		 *
> -		 * Alpha is .25
> -		 */
> -		glob_stats->avg_latency += (latency - glob_stats->avg_latency) / 4;
> +			glob_stats->avg_latency = latency;
> +			glob_stats->jitter = 0;
> +		} else {
> +			/*
> +			 * The jitter is calculated as statistical mean of interpacket
> +			 * delay variation. The "jitter estimate" is computed by taking
> +			 * the absolute values of the ipdv sequence and applying an
> +			 * exponential filter with parameter 1/16 to generate the
> +			 * estimate. i.e J=J+(|D(i-1,i)|-J)/16. Where J is jitter,
> +			 * D(i-1,i) is difference in latency of two consecutive packets
> +			 * i-1 and i.
> +			 * Reference: Calculated as per RFC 5481, sec 4.1,
> +			 * RFC 3393 sec 4.5, RFC 1889 sec.
> +			 */
> +			glob_stats->jitter += ((prev_latency - latency)
> +					       - glob_stats->jitter) / 16;
> +			if (latency < glob_stats->min_latency)
> +				glob_stats->min_latency = latency;
> +			if (latency > glob_stats->max_latency)
> +				glob_stats->max_latency = latency;
> +			/*
> +			 * The average latency is measured using exponential moving
> +			 * average, i.e. using EWMA
> +			 * https://en.wikipedia.org/wiki/Moving_average
> +			 *
> +			 * Alpha is .25
> +			 */
> +			glob_stats->avg_latency += (latency - glob_stats->avg_latency) / 4;
> +		}
> +
>  		prev_latency = latency;
>  	}
>  	rte_spinlock_unlock(&glob_stats->lock);
> -- 
> 2.43.0
>