Re: [dpdk-dev] Questions about rte_eth_link_speed_to_str API

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

Thanks Stephen,
While I think this option is more clear and simple:
+const char *
+rte_eth_link_speed_to_str(uint32_t link_speed)
+{
+#define SPEED_STRING_LEN 16
+	static char name[SPEED_STRING_LEN];
+
+	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;
+}

How about any others' opinions, thanks.

在 2021/9/14 14:59, Stephen Hemminger 写道:
> On Tue, 14 Sep 2021 11:25:44 +0800
> "Min Hu (Connor)" <humin29@huawei.com> wrote:
> 
>> Thanks Thomas,
>> 	I am not sure if we need to  print combined slaves speed.
>> 	How about others' opinion ? @all
>>
>> 	BTW, If yes, one possible option may be like that:
>> +const char *
>> +rte_eth_link_speed_to_str(uint32_t link_speed)
>> +{
>> +	char name[16];
>> +
>> +	if (link_speed == ETH_SPEED_NUM_NONE)
>> +		return "None";
>> +	if (link_speed == ETH_SPEED_NUM_NONE)
>> +		return "Unknown";
>> +	if (link_speed < ETH_SPEED_NUM_1G) {
>> +		snprintf(name, sizeof(name), "%u Mbps", link_speed);
>> +	} else {
>> +		snprintf(name, sizeof(name), "%u Mbps",
>> +			link_speed / ETH_SPEED_NUM_1G);
>> +	}
>> +
>> +	return name;
>> +}
>>
>> But the float value is difficult to handle, like 2.5 Gbps for show. Any
>> advices?
>>
>> 在 2021/9/13 18:26, Thomas Monjalon 写道:
>>> 13/09/2021 10:45, Min Hu (Connor):
>>>> Hi all,
>>>> 	I have questions about rte_eth_link_speed_to_str API.
>>>> 	The API converts link speed to string for display, But it only
>>>> supports the following speeds, like that:
>>>> 	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";
>>>>
>>>> 	In some cases, like bonding, for example, three slaves which
>>>> 	link speed are 10Gbps, so link speed of bonding port will be
>>>> 	30Gbps, but it shows "Invalid".
>>>>
>>>> 	Is this reasonable？ any comments will be welcome.
>>>
>>> Is it meaningful to print combined slaves speed?
>>> If yes, we can do better then this fixed switch/case logic,
>>> it shouldn't be too hard given it is a standard uint32_t value.
>>>
>>>
>>> .
>>>    
> 
> Since all the values are encoded numerically do some math.
> This is what iproute2 has evolved to doing..
> 
> 
> int print_color_rate(bool use_iec, enum output_type type, enum color_attr color,
>                       const char *key, const char *fmt, unsigned long long rate)
> {
>          unsigned long kilo = use_iec ? 1024 : 1000;
>          const char *str = use_iec ? "i" : "";
>          static char *units[5] = {"", "K", "M", "G", "T"};
>          char *buf;
>          int rc;
>          int i;
> 
>          if (_IS_JSON_CONTEXT(type))
>                  return print_color_lluint(type, color, key, "%llu", rate);
> 
>          rate <<= 3; /* bytes/sec -> bits/sec */
> 
>          for (i = 0; i < ARRAY_SIZE(units) - 1; i++)  {
>                  if (rate < kilo)
>                          break;
>                  if (((rate % kilo) != 0) && rate < 1000*kilo)
>                          break;
>                  rate /= kilo;
>          }
> 
>          rc = asprintf(&buf, "%.0f%s%sbit", (double)rate, units[i],
>                        i > 0 ? str : "");
>          if (rc < 0)
>                  return -1;
> 
>          rc = print_color_string(type, color, key, fmt, buf);
>          free(buf);
> }
>      
> 
> .
>