Re: [dpdk-dev] [RFC] ethdev: improve link speed to string

["Min Hu (Connor)" <humin29@huawei.com>]

Hi, Andrew,

在 2021/9/16 14:22, Andrew Rybchenko 写道:
> On 9/16/21 5:56 AM, Min Hu (Connor) wrote:
>> Currently, link speed to string only supports specific speeds, like 10M,
>> 100M, 1G etc.
>>
>> This patch expands support for any link speed which is over 1M and one
>> decimal place will kept for display at most.
>>
>> Signed-off-by: Min Hu (Connor) <humin29@huawei.com>
>> ---
>>   lib/ethdev/rte_ethdev.c | 34 +++++++++++++++++-----------------
>>   1 file changed, 17 insertions(+), 17 deletions(-)
>>
>> diff --git a/lib/ethdev/rte_ethdev.c b/lib/ethdev/rte_ethdev.c
>> index daf5ca9242..1d3b960305 100644
>> --- a/lib/ethdev/rte_ethdev.c
>> +++ b/lib/ethdev/rte_ethdev.c
>> @@ -2750,24 +2750,24 @@ rte_eth_link_get_nowait(uint16_t port_id, struct rte_eth_link *eth_link)
>>   const char *
>>   rte_eth_link_speed_to_str(uint32_t link_speed)
>>   {
>> -	switch (link_speed) {
>> -	case ETH_SPEED_NUM_NONE: return "None";
>> -	case ETH_SPEED_NUM_10M:  return "10 Mbps";
>> -	case ETH_SPEED_NUM_100M: return "100 Mbps";
>> -	case ETH_SPEED_NUM_1G:   return "1 Gbps";
>> -	case ETH_SPEED_NUM_2_5G: return "2.5 Gbps";
>> -	case ETH_SPEED_NUM_5G:   return "5 Gbps";
>> -	case ETH_SPEED_NUM_10G:  return "10 Gbps";
>> -	case ETH_SPEED_NUM_20G:  return "20 Gbps";
>> -	case ETH_SPEED_NUM_25G:  return "25 Gbps";
>> -	case ETH_SPEED_NUM_40G:  return "40 Gbps";
>> -	case ETH_SPEED_NUM_50G:  return "50 Gbps";
>> -	case ETH_SPEED_NUM_56G:  return "56 Gbps";
>> -	case ETH_SPEED_NUM_100G: return "100 Gbps";
>> -	case ETH_SPEED_NUM_200G: return "200 Gbps";
>> -	case ETH_SPEED_NUM_UNKNOWN: return "Unknown";
>> -	default: return "Invalid";
>> +#define SPEED_STRING_LEN 16
>> +	static char name[SPEED_STRING_LEN];
> 
> NACK
> 
> Nothing good will happen if you try to use the function to
> print two different link speeds in one log message.
You are right.
And use malloc for "name" will result in memory leakage, which is also
not a good option.

BTW, do you think if we need to modify the function 
"rte_eth_link_speed_to_str"?

> 
>> +
>> +	if (link_speed == ETH_SPEED_NUM_NONE)
>> +		return "None";
>> +	if (link_speed == ETH_SPEED_NUM_UNKNOWN)
>> +		return "Unknown";
>> +	if (link_speed < ETH_SPEED_NUM_1G) {
>> +		snprintf(name, sizeof(name), "%u Mbps", link_speed);
>> +	} else if (link_speed % ETH_SPEED_NUM_1G != 0) {
>> +		snprintf(name, sizeof(name), "%.1f Gbps",
>> +		(double)link_speed / ETH_SPEED_NUM_1G);
>> +	} else {
>> +		snprintf(name, sizeof(name), "%u Gbps",
>> +		link_speed / ETH_SPEED_NUM_1G);
>>   	}
>> +
>> +	return (const char *)name;
>>   }
>>   
>>   int
>>
> 
> .
>