[dpdk-dev] [PATCH] app/testpmd: fix statistics in multiple process

[dpdk-dev] [PATCH] app/testpmd: fix statistics in multiple process

[Min Hu (Connor)]

Currently, 'clear port stats all' in secondary will clear stats in PMD,
and also update stats which APP stores in 'ports[]' array in secondary
process, note that, that in primary process remains unchanged. So, when
'show fwd stats all' in primary process, stats in PMD may be less than
stats which APP stores in 'ports[]' array(the stats is different with
that in secondary). So forward statistics(stats in PMD minus stats
which APP stores in 'ports[]' array) will be wrong. Like this:
---------------------- Forward statistics for port 0  --------------
RX-packets: 18446744073703120168 RX-dropped: 18446744073704076766
RX-total: 18446744073697645318
TX-packets: 18446744073703122216 TX-dropped: 0
TX-total: 18446744073703122216
--------------------------------------------------------------------
Stats in PMD are shared between multiple processes, but stats which APP
stores have their own copies in multiple processes. And this will
result in bugs.

This patch will fix it by creating shared memory to store last stats for
multiple and secondary process in testpmd.

Fixes: 184de26c78d0 ("app/testpmd: support multi-process")

Signed-off-by: Min Hu (Connor) <humin29@huawei.com>
---
 app/test-pmd/config.c  |  4 +--
 app/test-pmd/testpmd.c | 63 ++++++++++++++++++++++++++++++++++++------
 app/test-pmd/testpmd.h |  2 +-
 3 files changed, 58 insertions(+), 11 deletions(-)

diff --git a/app/test-pmd/config.c b/app/test-pmd/config.c
index f5765b34f7..31fee009c4 100644
--- a/app/test-pmd/config.c
+++ b/app/test-pmd/config.c
@@ -265,7 +265,7 @@ nic_stats_clear(portid_t port_id)
 		return;
 	}
 
-	ret = rte_eth_stats_get(port_id, &ports[port_id].stats);
+	ret = rte_eth_stats_get(port_id, ports[port_id].stats);
 	if (ret != 0) {
 		if (ret < 0)
 			ret = -ret;
@@ -358,7 +358,7 @@ nic_xstats_clear(portid_t port_id)
 		return;
 	}
 
-	ret = rte_eth_stats_get(port_id, &ports[port_id].stats);
+	ret = rte_eth_stats_get(port_id, ports[port_id].stats);
 	if (ret != 0) {
 		if (ret < 0)
 			ret = -ret;
diff --git a/app/test-pmd/testpmd.c b/app/test-pmd/testpmd.c
index 97ae52e17e..2e5ab5f24e 100644
--- a/app/test-pmd/testpmd.c
+++ b/app/test-pmd/testpmd.c
@@ -84,6 +84,7 @@
 
 #define EXTMEM_HEAP_NAME "extmem"
 #define EXTBUF_ZONE_SIZE RTE_PGSIZE_2M
+#define TESTPMD_ETH_STATS_MZNAME "testpmd_eth_stats"
 
 uint16_t verbose_level = 0; /**< Silent by default. */
 int testpmd_logtype; /**< Log type for testpmd logs */
@@ -599,6 +600,46 @@ uint16_t gso_max_segment_size = RTE_ETHER_MAX_LEN - RTE_ETHER_CRC_LEN;
 /* Holds the registered mbuf dynamic flags names. */
 char dynf_names[64][RTE_MBUF_DYN_NAMESIZE];
 
+/* Memzone for storing ethdev last port statistics. */
+const struct rte_memzone *eth_stats_mz;
+
+static int
+eth_stats_zone_reserve(void)
+{
+	size_t len = RTE_MAX_ETHPORTS * sizeof(struct rte_eth_stats);
+
+	if (rte_eal_process_type() == RTE_PROC_PRIMARY) {
+		eth_stats_mz = rte_memzone_reserve_aligned(
+						TESTPMD_ETH_STATS_MZNAME, len,
+						SOCKET_ID_ANY, 0,
+						RTE_CACHE_LINE_SIZE);
+	} else {
+		eth_stats_mz = rte_memzone_lookup(TESTPMD_ETH_STATS_MZNAME);
+	}
+	if (eth_stats_mz == NULL)
+		return -1;
+
+	return 0;
+}
+
+static void
+eth_stats_zone_free(void)
+{
+	if (rte_eal_process_type() == RTE_PROC_PRIMARY)
+		rte_memzone_free(eth_stats_mz);
+}
+
+static void
+port_stats_init(portid_t pid)
+{
+	struct rte_eth_stats *buf = (struct rte_eth_stats *)eth_stats_mz->addr;
+	struct rte_port *port = &ports[pid];
+
+	port->stats = &buf[pid];
+	if (rte_eal_process_type() == RTE_PROC_PRIMARY)
+		memset(port->stats, 0, sizeof(struct rte_eth_stats));
+}
+
 /*
  * Helper function to check if socket is already discovered.
  * If yes, return positive value. If not, return zero.
@@ -1929,13 +1970,13 @@ fwd_stats_display(void)
 		port = &ports[pt_id];
 
 		rte_eth_stats_get(pt_id, &stats);
-		stats.ipackets -= port->stats.ipackets;
-		stats.opackets -= port->stats.opackets;
-		stats.ibytes -= port->stats.ibytes;
-		stats.obytes -= port->stats.obytes;
-		stats.imissed -= port->stats.imissed;
-		stats.oerrors -= port->stats.oerrors;
-		stats.rx_nombuf -= port->stats.rx_nombuf;
+		stats.ipackets -= port->stats->ipackets;
+		stats.opackets -= port->stats->opackets;
+		stats.ibytes -= port->stats->ibytes;
+		stats.obytes -= port->stats->obytes;
+		stats.imissed -= port->stats->imissed;
+		stats.oerrors -= port->stats->oerrors;
+		stats.rx_nombuf -= port->stats->rx_nombuf;
 
 		total_recv += stats.ipackets;
 		total_xmit += stats.opackets;
@@ -2027,7 +2068,7 @@ fwd_stats_reset(void)
 
 	for (i = 0; i < cur_fwd_config.nb_fwd_ports; i++) {
 		pt_id = fwd_ports_ids[i];
-		rte_eth_stats_get(pt_id, &ports[pt_id].stats);
+		rte_eth_stats_get(pt_id, ports[pt_id].stats);
 	}
 	for (sm_id = 0; sm_id < cur_fwd_config.nb_fwd_streams; sm_id++) {
 		struct fwd_stream *fs = fwd_streams[sm_id];
@@ -2888,6 +2929,7 @@ close_port(portid_t pid)
 			port_flow_flush(pi);
 			rte_eth_dev_close(pi);
 		}
+		eth_stats_zone_free();
 	}
 
 	remove_invalid_ports();
@@ -3572,6 +3614,7 @@ init_port_config(void)
 			port->dev_conf.intr_conf.lsc = 1;
 		if (rmv_interrupt && (*port->dev_info.dev_flags & RTE_ETH_DEV_INTR_RMV))
 			port->dev_conf.intr_conf.rmv = 1;
+		port_stats_init(pid);
 	}
 }
 
@@ -3882,6 +3925,10 @@ main(int argc, char** argv)
 		rte_exit(EXIT_FAILURE, "Cannot init EAL: %s\n",
 			 rte_strerror(rte_errno));
 
+	ret = eth_stats_zone_reserve();
+	if (ret != 0)
+		rte_exit(EXIT_FAILURE, "Allocate memzone ethdev stats failed");
+
 	ret = register_eth_event_callback();
 	if (ret != 0)
 		rte_exit(EXIT_FAILURE, "Cannot register for ethdev events");
diff --git a/app/test-pmd/testpmd.h b/app/test-pmd/testpmd.h
index 5863b2f43f..a48a302343 100644
--- a/app/test-pmd/testpmd.h
+++ b/app/test-pmd/testpmd.h
@@ -202,7 +202,7 @@ struct rte_port {
 	struct rte_eth_dev_info dev_info;   /**< PCI info + driver name */
 	struct rte_eth_conf     dev_conf;   /**< Port configuration. */
 	struct rte_ether_addr       eth_addr;   /**< Port ethernet address */
-	struct rte_eth_stats    stats;      /**< Last port statistics */
+	struct rte_eth_stats    *stats;      /**< Last port statistics */
 	unsigned int            socket_id;  /**< For NUMA support */
 	uint16_t		parse_tunnel:1; /**< Parse internal headers */
 	uint16_t                tso_segsz;  /**< Segmentation offload MSS for non-tunneled packets. */
-- 
2.33.0

Re: [dpdk-dev] [PATCH] app/testpmd: fix statistics in multiple process

[Li, Xiaoyun]

Hi

> -----Original Message-----
> From: Min Hu (Connor) <humin29@huawei.com>
> Sent: Tuesday, September 14, 2021 11:13
> To: dev@dpdk.org
> Cc: Yigit, Ferruh <ferruh.yigit@intel.com>; Li, Xiaoyun <xiaoyun.li@intel.com>
> Subject: [PATCH] app/testpmd: fix statistics in multiple process
> 
> Currently, 'clear port stats all' in secondary will clear stats in PMD, and also
> update stats which APP stores in 'ports[]' array in secondary process, note that,
> that in primary process remains unchanged. So, when 'show fwd stats all' in
> primary process, stats in PMD may be less than stats which APP stores in 'ports[]'
> array(the stats is different with that in secondary). So forward statistics(stats in
> PMD minus stats which APP stores in 'ports[]' array) will be wrong. Like this:
> ---------------------- Forward statistics for port 0  --------------
> RX-packets: 18446744073703120168 RX-dropped: 18446744073704076766
> RX-total: 18446744073697645318
> TX-packets: 18446744073703122216 TX-dropped: 0
> TX-total: 18446744073703122216
> --------------------------------------------------------------------
> Stats in PMD are shared between multiple processes, but stats which APP stores
> have their own copies in multiple processes. And this will result in bugs.
> 
> This patch will fix it by creating shared memory to store last stats for multiple
> and secondary process in testpmd.

Why not just limit "clear port stats " behavior to only primary process?
Is there any particular reason second process has to do clear stats?

Stats is quite complicate struct. I feel like it will have race condition issue if you allow two processes to clear it.
Only allow getting for multiple processes makes more sense.

Also your patch has issues even if this idea is accepted by others. Please see below.

> 
> Fixes: 184de26c78d0 ("app/testpmd: support multi-process")
> 
> Signed-off-by: Min Hu (Connor) <humin29@huawei.com>
> ---
>  app/test-pmd/config.c  |  4 +--
>  app/test-pmd/testpmd.c | 63 ++++++++++++++++++++++++++++++++++++------
>  app/test-pmd/testpmd.h |  2 +-
>  3 files changed, 58 insertions(+), 11 deletions(-)
> 
<snip>
> @@ -3572,6 +3614,7 @@ init_port_config(void)
>  			port->dev_conf.intr_conf.lsc = 1;
>  		if (rmv_interrupt && (*port->dev_info.dev_flags &
> RTE_ETH_DEV_INTR_RMV))
>  			port->dev_conf.intr_conf.rmv = 1;
> +		port_stats_init(pid);

Init_port_config is called in several places. Why init stats as 0 for port->stats here?
You did so. Then if user use cmd like "port config 0 rxq 2" which calls init_port_config, port->stats is cleared while device stats isn't.
Then the fwd stats you got will be wrong.

Please read code carefully. Port->stats will be reset as device stats when start_fwd. Not reset as 0.

Port->stats should be only cleared when you do clear_nic_stats. Otherwise, it doesn't make sense as "last port stats".

>  	}
>  }
> 
> @@ -3882,6 +3925,10 @@ main(int argc, char** argv)
>  		rte_exit(EXIT_FAILURE, "Cannot init EAL: %s\n",
>  			 rte_strerror(rte_errno));
> 
> +	ret = eth_stats_zone_reserve();
> +	if (ret != 0)
> +		rte_exit(EXIT_FAILURE, "Allocate memzone ethdev stats failed");
> +
>  	ret = register_eth_event_callback();
>  	if (ret != 0)
>  		rte_exit(EXIT_FAILURE, "Cannot register for ethdev events");
> diff --git a/app/test-pmd/testpmd.h b/app/test-pmd/testpmd.h index
> 5863b2f43f..a48a302343 100644
> --- a/app/test-pmd/testpmd.h
> +++ b/app/test-pmd/testpmd.h
> @@ -202,7 +202,7 @@ struct rte_port {
>  	struct rte_eth_dev_info dev_info;   /**< PCI info + driver name */
>  	struct rte_eth_conf     dev_conf;   /**< Port configuration. */
>  	struct rte_ether_addr       eth_addr;   /**< Port ethernet address */
> -	struct rte_eth_stats    stats;      /**< Last port statistics */
> +	struct rte_eth_stats    *stats;      /**< Last port statistics */
>  	unsigned int            socket_id;  /**< For NUMA support */
>  	uint16_t		parse_tunnel:1; /**< Parse internal headers */
>  	uint16_t                tso_segsz;  /**< Segmentation offload MSS for non-
> tunneled packets. */
> --
> 2.33.0

Re: [dpdk-dev] [PATCH] app/testpmd: fix statistics in multiple process

[Min Hu (Connor)]

Hi, Xiaoyun,

在 2021/9/16 13:17, Li, Xiaoyun 写道:
> Hi
> 
>> -----Original Message-----
>> From: Min Hu (Connor) <humin29@huawei.com>
>> Sent: Tuesday, September 14, 2021 11:13
>> To: dev@dpdk.org
>> Cc: Yigit, Ferruh <ferruh.yigit@intel.com>; Li, Xiaoyun <xiaoyun.li@intel.com>
>> Subject: [PATCH] app/testpmd: fix statistics in multiple process
>>
>> Currently, 'clear port stats all' in secondary will clear stats in PMD, and also
>> update stats which APP stores in 'ports[]' array in secondary process, note that,
>> that in primary process remains unchanged. So, when 'show fwd stats all' in
>> primary process, stats in PMD may be less than stats which APP stores in 'ports[]'
>> array(the stats is different with that in secondary). So forward statistics(stats in
>> PMD minus stats which APP stores in 'ports[]' array) will be wrong. Like this:
>> ---------------------- Forward statistics for port 0  --------------
>> RX-packets: 18446744073703120168 RX-dropped: 18446744073704076766
>> RX-total: 18446744073697645318
>> TX-packets: 18446744073703122216 TX-dropped: 0
>> TX-total: 18446744073703122216
>> --------------------------------------------------------------------
>> Stats in PMD are shared between multiple processes, but stats which APP stores
>> have their own copies in multiple processes. And this will result in bugs.
>>
>> This patch will fix it by creating shared memory to store last stats for multiple
>> and secondary process in testpmd.
> 
> Why not just limit "clear port stats " behavior to only primary process?
> Is there any particular reason second process has to do clear stats?
While, I have no idea if some particular reason exists second process 
has to do clear stats. I just want to implement this function.

> 
> Stats is quite complicate struct. I feel like it will have race condition issue if you allow two processes to clear it.

> Only allow getting for multiple processes makes more sense.
Yes, I agree with you, maybe I can add constrains in testpmd guide doc.
BTW, what abot any others' opinion ?

> 
> Also your patch has issues even if this idea is accepted by others. Please see below.
> 
>>
>> Fixes: 184de26c78d0 ("app/testpmd: support multi-process")
>>
>> Signed-off-by: Min Hu (Connor) <humin29@huawei.com>
>> ---
>>   app/test-pmd/config.c  |  4 +--
>>   app/test-pmd/testpmd.c | 63 ++++++++++++++++++++++++++++++++++++------
>>   app/test-pmd/testpmd.h |  2 +-
>>   3 files changed, 58 insertions(+), 11 deletions(-)
>>
> <snip>
>> @@ -3572,6 +3614,7 @@ init_port_config(void)
>>   			port->dev_conf.intr_conf.lsc = 1;
>>   		if (rmv_interrupt && (*port->dev_info.dev_flags &
>> RTE_ETH_DEV_INTR_RMV))
>>   			port->dev_conf.intr_conf.rmv = 1;
>> +		port_stats_init(pid);
> 
> Init_port_config is called in several places. Why init stats as 0 for port->stats here?
> You did so. Then if user use cmd like "port config 0 rxq 2" which calls init_port_config, port->stats is cleared while device stats isn't.
> Then the fwd stats you got will be wrong.
> 
> Please read code carefully. Port->stats will be reset as device stats when start_fwd. Not reset as 0.
> 
> Port->stats should be only cleared when you do clear_nic_stats. Otherwise, it doesn't make sense as "last port stats".
> 
I know your meaning.
Actually, My purpose for 'port_stats_init' is only called for all port
  at init stage. While 'init_port config' confusd me, May I can put the
'port_stats_init' in 'init_config', this may can work out.

Thanks.


>>   	}
>>   }
>>
>> @@ -3882,6 +3925,10 @@ main(int argc, char** argv)
>>   		rte_exit(EXIT_FAILURE, "Cannot init EAL: %s\n",
>>   			 rte_strerror(rte_errno));
>>
>> +	ret = eth_stats_zone_reserve();
>> +	if (ret != 0)
>> +		rte_exit(EXIT_FAILURE, "Allocate memzone ethdev stats failed");
>> +
>>   	ret = register_eth_event_callback();
>>   	if (ret != 0)
>>   		rte_exit(EXIT_FAILURE, "Cannot register for ethdev events");
>> diff --git a/app/test-pmd/testpmd.h b/app/test-pmd/testpmd.h index
>> 5863b2f43f..a48a302343 100644
>> --- a/app/test-pmd/testpmd.h
>> +++ b/app/test-pmd/testpmd.h
>> @@ -202,7 +202,7 @@ struct rte_port {
>>   	struct rte_eth_dev_info dev_info;   /**< PCI info + driver name */
>>   	struct rte_eth_conf     dev_conf;   /**< Port configuration. */
>>   	struct rte_ether_addr       eth_addr;   /**< Port ethernet address */
>> -	struct rte_eth_stats    stats;      /**< Last port statistics */
>> +	struct rte_eth_stats    *stats;      /**< Last port statistics */
>>   	unsigned int            socket_id;  /**< For NUMA support */
>>   	uint16_t		parse_tunnel:1; /**< Parse internal headers */
>>   	uint16_t                tso_segsz;  /**< Segmentation offload MSS for non-
>> tunneled packets. */
>> --
>> 2.33.0
> 
> .
> 

Re: [dpdk-dev] [PATCH] app/testpmd: fix statistics in multiple process

[Ferruh Yigit]

On 9/17/2021 4:33 AM, Min Hu (Connor) wrote:
> Hi, Xiaoyun,
> 
> 在 2021/9/16 13:17, Li, Xiaoyun 写道:
>> Hi
>>
>>> -----Original Message-----
>>> From: Min Hu (Connor) <humin29@huawei.com>
>>> Sent: Tuesday, September 14, 2021 11:13
>>> To: dev@dpdk.org
>>> Cc: Yigit, Ferruh <ferruh.yigit@intel.com>; Li, Xiaoyun <xiaoyun.li@intel.com>
>>> Subject: [PATCH] app/testpmd: fix statistics in multiple process
>>>
>>> Currently, 'clear port stats all' in secondary will clear stats in PMD, and also
>>> update stats which APP stores in 'ports[]' array in secondary process, note that,
>>> that in primary process remains unchanged. So, when 'show fwd stats all' in
>>> primary process, stats in PMD may be less than stats which APP stores in 'ports[]'
>>> array(the stats is different with that in secondary). So forward statistics(stats in
>>> PMD minus stats which APP stores in 'ports[]' array) will be wrong. Like this:
>>> ---------------------- Forward statistics for port 0  --------------
>>> RX-packets: 18446744073703120168 RX-dropped: 18446744073704076766
>>> RX-total: 18446744073697645318
>>> TX-packets: 18446744073703122216 TX-dropped: 0
>>> TX-total: 18446744073703122216
>>> --------------------------------------------------------------------
>>> Stats in PMD are shared between multiple processes, but stats which APP stores
>>> have their own copies in multiple processes. And this will result in bugs.
>>>
>>> This patch will fix it by creating shared memory to store last stats for multiple
>>> and secondary process in testpmd.
>>
>> Why not just limit "clear port stats " behavior to only primary process?
>> Is there any particular reason second process has to do clear stats?
> While, I have no idea if some particular reason exists second process has to do clear stats. I just want to implement this function.
> 
>>
>> Stats is quite complicate struct. I feel like it will have race condition issue if you allow two processes to clear it.
> 
>> Only allow getting for multiple processes makes more sense.
> Yes, I agree with you, maybe I can add constrains in testpmd guide doc.
> BTW, what abot any others' opinion ?
> 

I agree with Xiaoyun on possible race conditions, and to restrict the secondary
to read the stats but not clear it.

>>
>> Also your patch has issues even if this idea is accepted by others. Please see below.
>>
>>>
>>> Fixes: 184de26c78d0 ("app/testpmd: support multi-process")
>>>
>>> Signed-off-by: Min Hu (Connor) <humin29@huawei.com>
>>> ---
>>>   app/test-pmd/config.c  |  4 +--
>>>   app/test-pmd/testpmd.c | 63 ++++++++++++++++++++++++++++++++++++------
>>>   app/test-pmd/testpmd.h |  2 +-
>>>   3 files changed, 58 insertions(+), 11 deletions(-)
>>>
>> <snip>
>>> @@ -3572,6 +3614,7 @@ init_port_config(void)
>>>               port->dev_conf.intr_conf.lsc = 1;
>>>           if (rmv_interrupt && (*port->dev_info.dev_flags &
>>> RTE_ETH_DEV_INTR_RMV))
>>>               port->dev_conf.intr_conf.rmv = 1;
>>> +        port_stats_init(pid);
>>
>> Init_port_config is called in several places. Why init stats as 0 for port->stats here?
>> You did so. Then if user use cmd like "port config 0 rxq 2" which calls init_port_config, port->stats is cleared while device stats isn't.
>> Then the fwd stats you got will be wrong.
>>
>> Please read code carefully. Port->stats will be reset as device stats when start_fwd. Not reset as 0.
>>
>> Port->stats should be only cleared when you do clear_nic_stats. Otherwise, it doesn't make sense as "last port stats".
>>
> I know your meaning.
> Actually, My purpose for 'port_stats_init' is only called for all port
>   at init stage. While 'init_port config' confusd me, May I can put the
> 'port_stats_init' in 'init_config', this may can work out.
> 
> Thanks.
> 
> 
>>>       }
>>>   }
>>>
>>> @@ -3882,6 +3925,10 @@ main(int argc, char** argv)
>>>           rte_exit(EXIT_FAILURE, "Cannot init EAL: %s\n",
>>>                rte_strerror(rte_errno));
>>>
>>> +    ret = eth_stats_zone_reserve();
>>> +    if (ret != 0)
>>> +        rte_exit(EXIT_FAILURE, "Allocate memzone ethdev stats failed");
>>> +
>>>       ret = register_eth_event_callback();
>>>       if (ret != 0)
>>>           rte_exit(EXIT_FAILURE, "Cannot register for ethdev events");
>>> diff --git a/app/test-pmd/testpmd.h b/app/test-pmd/testpmd.h index
>>> 5863b2f43f..a48a302343 100644
>>> --- a/app/test-pmd/testpmd.h
>>> +++ b/app/test-pmd/testpmd.h
>>> @@ -202,7 +202,7 @@ struct rte_port {
>>>       struct rte_eth_dev_info dev_info;   /**< PCI info + driver name */
>>>       struct rte_eth_conf     dev_conf;   /**< Port configuration. */
>>>       struct rte_ether_addr       eth_addr;   /**< Port ethernet address */
>>> -    struct rte_eth_stats    stats;      /**< Last port statistics */
>>> +    struct rte_eth_stats    *stats;      /**< Last port statistics */
>>>       unsigned int            socket_id;  /**< For NUMA support */
>>>       uint16_t        parse_tunnel:1; /**< Parse internal headers */
>>>       uint16_t                tso_segsz;  /**< Segmentation offload MSS for non-
>>> tunneled packets. */
>>> -- 
>>> 2.33.0
>>
>> .
>>

Re: [dpdk-dev] [PATCH] app/testpmd: fix statistics in multiple process

[Min Hu (Connor)]

在 2021/10/27 0:22, Ferruh Yigit 写道:
> On 9/17/2021 4:33 AM, Min Hu (Connor) wrote:
>> Hi, Xiaoyun,
>>
>> 在 2021/9/16 13:17, Li, Xiaoyun 写道:
>>> Hi
>>>
>>>> -----Original Message-----
>>>> From: Min Hu (Connor) <humin29@huawei.com>
>>>> Sent: Tuesday, September 14, 2021 11:13
>>>> To: dev@dpdk.org
>>>> Cc: Yigit, Ferruh <ferruh.yigit@intel.com>; Li, Xiaoyun 
>>>> <xiaoyun.li@intel.com>
>>>> Subject: [PATCH] app/testpmd: fix statistics in multiple process
>>>>
>>>> Currently, 'clear port stats all' in secondary will clear stats in 
>>>> PMD, and also
>>>> update stats which APP stores in 'ports[]' array in secondary 
>>>> process, note that,
>>>> that in primary process remains unchanged. So, when 'show fwd stats 
>>>> all' in
>>>> primary process, stats in PMD may be less than stats which APP 
>>>> stores in 'ports[]'
>>>> array(the stats is different with that in secondary). So forward 
>>>> statistics(stats in
>>>> PMD minus stats which APP stores in 'ports[]' array) will be wrong. 
>>>> Like this:
>>>> ---------------------- Forward statistics for port 0  --------------
>>>> RX-packets: 18446744073703120168 RX-dropped: 18446744073704076766
>>>> RX-total: 18446744073697645318
>>>> TX-packets: 18446744073703122216 TX-dropped: 0
>>>> TX-total: 18446744073703122216
>>>> --------------------------------------------------------------------
>>>> Stats in PMD are shared between multiple processes, but stats which 
>>>> APP stores
>>>> have their own copies in multiple processes. And this will result in 
>>>> bugs.
>>>>
>>>> This patch will fix it by creating shared memory to store last stats 
>>>> for multiple
>>>> and secondary process in testpmd.
>>>
>>> Why not just limit "clear port stats " behavior to only primary process?
>>> Is there any particular reason second process has to do clear stats?
>> While, I have no idea if some particular reason exists second process 
>> has to do clear stats. I just want to implement this function.
>>
>>>
>>> Stats is quite complicate struct. I feel like it will have race 
>>> condition issue if you allow two processes to clear it.
>>
>>> Only allow getting for multiple processes makes more sense.
>> Yes, I agree with you, maybe I can add constrains in testpmd guide doc.
>> BTW, what abot any others' opinion ?
>>
> 
> I agree with Xiaoyun on possible race conditions, and to restrict the 
> secondary
> to read the stats but not clear it.
> 
Got it, this patch can be abandoned, thanks.
>>>
>>> Also your patch has issues even if this idea is accepted by others. 
>>> Please see below.
>>>
>>>>
>>>> Fixes: 184de26c78d0 ("app/testpmd: support multi-process")
>>>>
>>>> Signed-off-by: Min Hu (Connor) <humin29@huawei.com>
>>>> ---
>>>>   app/test-pmd/config.c  |  4 +--
>>>>   app/test-pmd/testpmd.c | 63 
>>>> ++++++++++++++++++++++++++++++++++++------
>>>>   app/test-pmd/testpmd.h |  2 +-
>>>>   3 files changed, 58 insertions(+), 11 deletions(-)
>>>>
>>> <snip>
>>>> @@ -3572,6 +3614,7 @@ init_port_config(void)
>>>>               port->dev_conf.intr_conf.lsc = 1;
>>>>           if (rmv_interrupt && (*port->dev_info.dev_flags &
>>>> RTE_ETH_DEV_INTR_RMV))
>>>>               port->dev_conf.intr_conf.rmv = 1;
>>>> +        port_stats_init(pid);
>>>
>>> Init_port_config is called in several places. Why init stats as 0 for 
>>> port->stats here?
>>> You did so. Then if user use cmd like "port config 0 rxq 2" which 
>>> calls init_port_config, port->stats is cleared while device stats isn't.
>>> Then the fwd stats you got will be wrong.
>>>
>>> Please read code carefully. Port->stats will be reset as device stats 
>>> when start_fwd. Not reset as 0.
>>>
>>> Port->stats should be only cleared when you do clear_nic_stats. 
>>> Otherwise, it doesn't make sense as "last port stats".
>>>
>> I know your meaning.
>> Actually, My purpose for 'port_stats_init' is only called for all port
>>   at init stage. While 'init_port config' confusd me, May I can put the
>> 'port_stats_init' in 'init_config', this may can work out.
>>
>> Thanks.
>>
>>
>>>>       }
>>>>   }
>>>>
>>>> @@ -3882,6 +3925,10 @@ main(int argc, char** argv)
>>>>           rte_exit(EXIT_FAILURE, "Cannot init EAL: %s\n",
>>>>                rte_strerror(rte_errno));
>>>>
>>>> +    ret = eth_stats_zone_reserve();
>>>> +    if (ret != 0)
>>>> +        rte_exit(EXIT_FAILURE, "Allocate memzone ethdev stats 
>>>> failed");
>>>> +
>>>>       ret = register_eth_event_callback();
>>>>       if (ret != 0)
>>>>           rte_exit(EXIT_FAILURE, "Cannot register for ethdev events");
>>>> diff --git a/app/test-pmd/testpmd.h b/app/test-pmd/testpmd.h index
>>>> 5863b2f43f..a48a302343 100644
>>>> --- a/app/test-pmd/testpmd.h
>>>> +++ b/app/test-pmd/testpmd.h
>>>> @@ -202,7 +202,7 @@ struct rte_port {
>>>>       struct rte_eth_dev_info dev_info;   /**< PCI info + driver 
>>>> name */
>>>>       struct rte_eth_conf     dev_conf;   /**< Port configuration. */
>>>>       struct rte_ether_addr       eth_addr;   /**< Port ethernet 
>>>> address */
>>>> -    struct rte_eth_stats    stats;      /**< Last port statistics */
>>>> +    struct rte_eth_stats    *stats;      /**< Last port statistics */
>>>>       unsigned int            socket_id;  /**< For NUMA support */
>>>>       uint16_t        parse_tunnel:1; /**< Parse internal headers */
>>>>       uint16_t                tso_segsz;  /**< Segmentation offload 
>>>> MSS for non-
>>>> tunneled packets. */
>>>> -- 
>>>> 2.33.0
>>>
>>> .
>>>
> 
> .