Re: [dpdk-dev] [PATCH 5/5] librte_ethdev: add to use apistats

[Hideyuki Yamashita <yamashita.hideyuki@ntt-tx.co.jp>]

Hello,

Thanks for your comments.
Please see my comments inline tagged with [HY].

> Hi,
> 
> > 
> > This patch modifies to use apistats by librte_ethdev.
> > 
> > Signed-off-by: Hideyuki Yamashita <yamashtia.hideyuki@ntt-tx.co.jp>
> > ---
> >  lib/librte_ethdev/meson.build    |  6 ++-
> >  lib/librte_ethdev/rte_apistats.c | 64 ++++++++++++++++++++++++++++++++
> >  lib/librte_ethdev/rte_apistats.h | 64 ++++++++++++++++++++++++++++++++
> >  lib/librte_ethdev/rte_ethdev.h   |  7 ++++
> >  lib/librte_ethdev/version.map    |  5 +++
> >  5 files changed, 144 insertions(+), 2 deletions(-)
> >  create mode 100644 lib/librte_ethdev/rte_apistats.c
> >  create mode 100644 lib/librte_ethdev/rte_apistats.h
> > 
> > diff --git a/lib/librte_ethdev/meson.build b/lib/librte_ethdev/meson.build
> > index e4b6102..d03e784 100644
> > --- a/lib/librte_ethdev/meson.build
> > +++ b/lib/librte_ethdev/meson.build
> > @@ -8,7 +8,8 @@ sources = files('ethdev_private.c',
> >  	'rte_ethdev.c',
> >  	'rte_flow.c',
> >  	'rte_mtr.c',
> > -	'rte_tm.c')
> > +	'rte_tm.c' ,
> > +        'rte_apistats.c')
> > 
> >  headers = files('rte_ethdev.h',
> >  	'rte_ethdev_driver.h',
> > @@ -24,6 +25,7 @@ headers = files('rte_ethdev.h',
> >  	'rte_mtr.h',
> >  	'rte_mtr_driver.h',
> >  	'rte_tm.h',
> > -	'rte_tm_driver.h')
> > +	'rte_tm_driver.h',
> > +        'rte_apistats.h')
> > 
> >  deps += ['net', 'kvargs', 'meter', 'telemetry']
> > diff --git a/lib/librte_ethdev/rte_apistats.c b/lib/librte_ethdev/rte_apistats.c
> > new file mode 100644
> > index 0000000..c4bde34
> > --- /dev/null
> > +++ b/lib/librte_ethdev/rte_apistats.c
> > @@ -0,0 +1,64 @@
> > +/* SPDX-License-Identifier: BSD-3-Clause
> > + * Copyright(c) 2019 NTT TechnoCross Corporation
> > + */
> > +
> > +
> > +#include <unistd.h>
> > +#include <sys/types.h>
> > +#include <string.h>
> > +#include <rte_log.h>
> > +#include <rte_memzone.h>
> > +#include <rte_lcore.h>
> > +
> > +#include "rte_apistats.h"
> > +
> > +/* Macros for printing using RTE_LOG */
> > +#define RTE_LOGTYPE_APISTATS RTE_LOGTYPE_USER1
> > +
> > +#define MZ_APISTATS "rte_apistats"
> > +
> > +struct rte_apistats *rte_apicounts;
> > +
> > +int rte_apistats_init(void)
> > +{
> > +	int i;
> > +	const struct rte_memzone *mz = NULL;
> > +	const unsigned int flags = 0;
> > +
> > +	/** Allocate stats in shared memory fo multi process support */
> > +	if (rte_eal_process_type() == RTE_PROC_SECONDARY) {
> > +		mz = rte_memzone_lookup(MZ_APISTATS);
> > +		if (mz == NULL) {
> > +			RTE_LOG(ERR, APISTATS, "Cannot get info structure\n");
> > +			return -1;
> > +		}
> > +		rte_apicounts = mz->addr;
> > +	} else {
> > +		/* RTE_PROC_PRIMARY */
> > +		mz = rte_memzone_reserve(MZ_APISTATS, sizeof(*rte_apicounts),
> > +			rte_socket_id(), flags);
> > +		if (mz == NULL) {
> > +			RTE_LOG(ERR, APISTATS, "Cannot reserve memory zone\n");
> > +			return -ENOMEM;
> > +		}
> > +		rte_apicounts = mz->addr;
> > +		memset(rte_apicounts, 0, sizeof(*rte_apicounts));
> > +	}
> > +
> > +	/* set up array for data */
> > +	RTE_LCORE_FOREACH(i) {
> > +		rte_apicounts->lcoreid_list[i] = 1;
> > +		RTE_LOG(INFO, APISTATS, "Enable core usage for lcore %u\n", i);
> > +	}
> > +	return 0;
> > +}
> > +
> > +int rte_apistats_uninit(void)
> > +{
> > +	const struct rte_memzone *mz = NULL;
> > +	/* free up the memzone */
> > +	mz = rte_memzone_lookup(MZ_APISTATS);
> > +	if (mz)
> > +		rte_memzone_free(mz);
> > +	return 0;
> > +}
> > diff --git a/lib/librte_ethdev/rte_apistats.h b/lib/librte_ethdev/rte_apistats.h
> > new file mode 100644
> > index 0000000..afea50e
> > --- /dev/null
> > +++ b/lib/librte_ethdev/rte_apistats.h
> > @@ -0,0 +1,64 @@
> > +/* SPDX-License-Identifier: BSD-3-Clause
> > + * Copyright(c) 2019 NTT TechnoCross Corporation
> > + */
> > +
> > +#ifndef _RTE_APISTATS_H_
> > +#define _RTE_APISTATS_H_
> > +
> > +/**
> > + * @file
> > + * RTE apistats
> > + *
> > + * library to provide rte_rx_burst/tx_burst api stats.
> > + */
> > +
> > +
> > +#ifdef __cplusplus
> > +extern "C" {
> > +#endif
> > +
> > +#include <rte_compat.h>
> > +#include <rte_lcore.h>
> > +
> > +/**
> > + * A structure for rte_rx_burst/tx_burst api statistics.
> > + */
> > +struct rte_apistats {
> > +	int lcoreid_list[RTE_MAX_LCORE];        /**< In use lcoreid list */
> > +	/**< Total rte_rx_burst call counts */
> > +	uint64_t rx_burst_counts[RTE_MAX_LCORE];
> > +
> > +	/**< Total rte_tx_burst call counts */
> > +	uint64_t tx_burst_counts[RTE_MAX_LCORE];
> > +};
> > +
> > +extern struct rte_apistats *rte_apicounts;
> > +
> > +/**
> > + *  Initialize rte_rx_burst/tx_burst call count area.
> > + *  @b EXPERIMENTAL: this API may change without prior notice.
> > + *
> > + *  @return
> > + *   -1     : On error
> > + *   -ENOMEM: On error
> > + *    0     : On success
> > + */
> > +__rte_experimental
> > +int rte_apistats_init(void);
> > +
> > +/**
> > + *  Clean up and free memory.
> > + *  @b EXPERIMENTAL: this API may change without prior notice.
> > + *
> > + *  @return
> > + *   -1: On error
> > + *    0: On success
> > + */
> > +__rte_experimental
> > +int rte_apistats_uninit(void);
> > +
> > +#ifdef __cplusplus
> > +}
> > +#endif
> > +
> > +#endif /* _RTE_APISTATS_H_ */
> > diff --git a/lib/librte_ethdev/rte_ethdev.h b/lib/librte_ethdev/rte_ethdev.h
> > index f5f8919..bef9bc6 100644
> > --- a/lib/librte_ethdev/rte_ethdev.h
> > +++ b/lib/librte_ethdev/rte_ethdev.h
> > @@ -160,6 +160,7 @@ extern "C" {
> > 
> >  #include "rte_ethdev_trace_fp.h"
> >  #include "rte_dev_info.h"
> > +#include <rte_apistats.h>
> > 
> >  extern int rte_eth_dev_logtype;
> > 
> > @@ -4849,6 +4850,9 @@ rte_eth_rx_burst(uint16_t port_id, uint16_t queue_id,
> >  	nb_rx = (*dev->rx_pkt_burst)(dev->data->rx_queues[queue_id],
> >  				     rx_pkts, nb_pkts);
> > 
> > +	int lcore_id = rte_lcore_id();
> > +	rte_apicounts->rx_burst_counts[lcore_id]++;
> 
> There are few problems with current implementation:
> 1.  rx_burst() can be called by non-EAL thread (rte_lcore_id() == -1)
>     In that case it would cause a crash.
[HY]
Thanks for your info.
I think by adding code like following.

     if(rte_lcore_id() = -1){
		return
      }


> 2. Because of the layout of struct rte_apistats it would cause significant
>     performance degradation (false cache-lines sharing).
[HY]
I think you are correct.
This affects change in core 1 to all other cores
even thogh change in core 1 does NOT affect other cores.

Root cause is using array like [RTE_MAX_LCORE], correct?
I will change it in revised patcheset.

+struct rte_apistats {
+       int lcoreid_list[RTE_MAX_LCORE];        /**< In use lcoreid list */
+       /**< Total rte_rx_burst call counts */
+       uint64_t rx_burst_counts[RTE_MAX_LCORE];
+
+       /**< Total rte_tx_burst call counts */
+       uint64_t tx_burst_counts[RTE_MAX_LCORE];
+};


> As a generic one: such sort of statistics can be easily collected by the app itself.
> Either by just incrementing counters before rx/tx_burst function call directly or
> via rx/tx callbacks.
> So I don't see any point to push it inside ethdev layer.  
> Konstantin
[HY]
You are correct.
Application can do it.
But if applications want to do it, then every applicaiton needs 
to do it.
The reason why I propose my patchset is to provide such
common function (count invocation of rx_burst/tx_burst)
so that application only needs to "retrieve the information".

I think it is benefitical than all application  do similar thing.
Your feedback is highly appreciated.

Thanks!
BR,
Hideyuki Yamashita
NTT TechnoCross

> >  #ifdef RTE_ETHDEV_RXTX_CALLBACKS
> >  	struct rte_eth_rxtx_callback *cb;
> > 
> > @@ -5124,6 +5128,9 @@ rte_eth_tx_burst(uint16_t port_id, uint16_t queue_id,
> >  	}
> >  #endif
> > 
> > +	int lcore_id = rte_lcore_id();
> > +	rte_apicounts->tx_burst_counts[lcore_id]++;
> >  #ifdef RTE_ETHDEV_RXTX_CALLBACKS
> >  	struct rte_eth_rxtx_callback *cb;
> > 
> > diff --git a/lib/librte_ethdev/version.map b/lib/librte_ethdev/version.map
> > index d3f5410..adea432 100644
> > --- a/lib/librte_ethdev/version.map
> > +++ b/lib/librte_ethdev/version.map
> > @@ -240,6 +240,11 @@ EXPERIMENTAL {
> >  	rte_flow_get_restore_info;
> >  	rte_flow_tunnel_action_decap_release;
> >  	rte_flow_tunnel_item_release;
> > +
> > +        # added in 21.02
> > +        rte_apistats_init;
> > +        rte_apistats_uninit;
> > +        rte_apicounts;
> >  };
> > 
> >  INTERNAL {
> > --
> > 2.18.0