[EXT] Re: [PATCH 1/6] ethdev: add trace points

[Ankur Dwivedi]

Hi Andrew,

>-----Original Message-----
>From: Andrew Rybchenko <andrew.rybchenko at oktetlabs.ru>
>Sent: Monday, September 12, 2022 4:30 PM
>To: Ankur Dwivedi <adwivedi at marvell.com>; dev at dpdk.org
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>Subject: [EXT] Re: [PATCH 1/6] ethdev: add trace points
>
>External Email
>
>----------------------------------------------------------------------
>On 8/4/22 16:44, Ankur Dwivedi wrote:
>> Add trace points for ethdev functions.
>>
>> Signed-off-by: Ankur Dwivedi <adwivedi at marvell.com>
>> ---
>
>[snip]
>
>> diff --git a/lib/ethdev/rte_ethdev.c b/lib/ethdev/rte_ethdev.c index
>> 1979dc0850..a6fb370b22 100644
>> --- a/lib/ethdev/rte_ethdev.c
>> +++ b/lib/ethdev/rte_ethdev.c
>
>[snip]
>
>> @@ -525,6 +536,7 @@ rte_eth_dev_owner_delete(const uint64_t
>owner_id)
>>
>>   	rte_spinlock_unlock(&eth_dev_shared_data->ownership_lock);
>>
>> +	rte_ethdev_trace_owner_delete(owner_id, ret);
>
>I'm wondering why trace is sometimes added in the middle of the function,
>but in the majority of cases it is added as the first or the last action. Is there
>any logical/guidelines behind it?
In this case for printing the return value the trace was added at the end. I can change it if not required.
The logic which I used was to log at least the input arguments of a function and in some cases also log important information(according to me) if possible.For example in rte_eth_tx_buffer_count_callback() I was also logging the count at the end. Similar logic in rte_eth_link_get_nowait().
Please let me know your views.
>
>>   	return ret;
>>   }
>>
>
>[snip]
>
>> diff --git a/lib/ethdev/rte_ethdev_trace.h
>> b/lib/ethdev/rte_ethdev_trace.h index 1491c815c3..de728d355d 100644
>> --- a/lib/ethdev/rte_ethdev_trace.h
>> +++ b/lib/ethdev/rte_ethdev_trace.h
>
>[snip]
>
>> +RTE_TRACE_POINT(
>
>Shouldn't it be RTE_TRACE_POINT_FP? Isn't it fast path?
Yes it is fastpath. Will make it as fastpath in v2.
>
>> +	rte_eth_trace_call_rx_callbacks,
>> +	RTE_TRACE_POINT_ARGS(uint16_t port_id, uint16_t queue_id,
>> +		struct rte_mbuf **rx_pkts, uint16_t nb_rx,
>> +		uint16_t nb_pkts, void *opaque),
>> +	rte_trace_point_emit_u16(port_id);
>> +	rte_trace_point_emit_u16(queue_id);
>> +	rte_trace_point_emit_ptr(rx_pkts);
>> +	rte_trace_point_emit_u16(nb_rx);
>> +	rte_trace_point_emit_u16(nb_pkts);
>> +	rte_trace_point_emit_ptr(opaque);
>> +)
>> +
>> +RTE_TRACE_POINT(
>
>same here
Yes it is fastpath. Will make it as fastpath in v2.
>
>> +	rte_eth_trace_call_tx_callbacks,
>> +	RTE_TRACE_POINT_ARGS(uint16_t port_id, uint16_t queue_id,
>> +		struct rte_mbuf **tx_pkts, uint16_t nb_pkts,
>> +		void *opaque),
>> +	rte_trace_point_emit_u16(port_id);
>> +	rte_trace_point_emit_u16(queue_id);
>> +	rte_trace_point_emit_ptr(tx_pkts);
>> +	rte_trace_point_emit_u16(nb_pkts);
>> +	rte_trace_point_emit_ptr(opaque);
>> +)
>> +
>
>[snip]
>
>> +RTE_TRACE_POINT(
>> +	rte_ethdev_trace_info_get,
>> +	RTE_TRACE_POINT_ARGS(uint16_t port_id,
>> +		struct rte_eth_dev_info *dev_info),
>> +	rte_trace_point_emit_u16(port_id);
>> +	rte_trace_point_emit_string(dev_info->driver_name);
>> +	rte_trace_point_emit_u32(dev_info->if_index);
>> +	rte_trace_point_emit_u16(dev_info->min_mtu);
>> +	rte_trace_point_emit_u16(dev_info->max_mtu);
>> +	rte_trace_point_emit_u32(dev_info->min_rx_bufsize);
>> +	rte_trace_point_emit_u32(dev_info->max_rx_pktlen);
>> +	rte_trace_point_emit_u64(dev_info->rx_offload_capa);
>> +	rte_trace_point_emit_u64(dev_info->tx_offload_capa);
>> +	rte_trace_point_emit_u64(dev_info->rx_queue_offload_capa);
>> +	rte_trace_point_emit_u64(dev_info->tx_queue_offload_capa);
>> +	rte_trace_point_emit_u16(dev_info->reta_size);
>> +	rte_trace_point_emit_u8(dev_info->hash_key_size);
>> +	rte_trace_point_emit_u16(dev_info->nb_rx_queues);
>> +	rte_trace_point_emit_u16(dev_info->nb_tx_queues);
>
>How to make a choice which information should be included above?
In this case dev_info information is logged which might be of interest.
>
>> +)
>> +
>
>[snip]