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SubjectRe: GT/s vs Gbps for PCIe bus speed
Krzysztof Halasa wrote:
> Stefan Assmann <sassmann@redhat.com> writes:
>
>> IMHO this is rather confusing, as most people don't know what GT/s means.
>
> It's trivial to look it up, isn't it?
>
>> So I'd suggest the following change:
>>
>> --- a/drivers/pci/hotplug/pci_hotplug_core.c
>> +++ b/drivers/pci/hotplug/pci_hotplug_core.c
>> @@ -86,8 +86,8 @@ static char *pci_bus_speed_strings[] = {
>> "66 MHz PCIX 533", /* 0x11 */
>> "100 MHz PCIX 533", /* 0x12 */
>> "133 MHz PCIX 533", /* 0x13 */
>> - "2.5 GT/s PCI-E", /* 0x14 */
>> - "5.0 GT/s PCI-E", /* 0x15 */
>> + "2.5 Gbps PCI-E", /* 0x14 */
>> + "5.0 Gbps PCI-E", /* 0x15 */
>
> Isn't it like calling 100BASE-TX a 125 Mb/s? _That_ would be confusing.
> BTW PCI-E can be multi-lane so Mb/s (and even MB/s) don't make sense.
> I guess many people don't know what a MHz is either but we don't say
> 133 MHz = 133 Mbps.

so, maybe the right terms are
2.5 GHz PCI-E
5.0 GHz PCI-E

No matter how many lanes, or how the data is sent (long or short bursts),
the frequency rate is a constant.

So, the data rate is not stated, just the cycle rate.
This would follow the PCIX syntax as well, which is
void of bandwidth illusions.

- Don

ps -- "GT/s" isn't even defined in the PCIe spec, just
blindly introduced, and unjustified in its use.
..... too much marketing-speak in PCI SIG ...



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