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SubjectRe: [PATCH 1/9] PCI: sysfs: Export available PCIe bandwidth
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On 09/05/2018 02:26 AM, Stephen Hemminger wrote:
> On Mon, 3 Sep 2018 13:02:28 -0500
> Alexandru Gagniuc <mr.nuke.me@gmail.com> wrote:
>
>> For certain bandwidth-critical devices (e.g. multi-port network cards)
>> it is useful to know the available bandwidth to the root complex. This
>> information is only available via the system log, which doesn't
>> account for link degradation after probing.
>>
>> With a sysfs attribute, we can computes the bandwidth on-demand, and
>> will detect degraded links.
>>
>> Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
>
> In other places (like /sys/class/net/eth0/speed) only the raw value is printed
> without suffix. The general convention in sysfs is that it should be one value
> per file and in more raw format. So why not just print it in bits/sec without
> suffix?

I wanted to be consistent with other PCIe exports that use units.For
example:

/sys/devices/pci0000:3a/0000:3a:00.0/0000:3b:00.0/0000:3c:05.0/max_link_speed:8
GT/s
/sys/devices/pci0000:3a/0000:3a:00.0/0000:3b:00.0/0000:3c:05.0/current_link_speed:2.5
GT/s
/sys/bus/pci/slots/182/cur_bus_speed:2.5 GT/s PCIe
/sys/bus/pci/slots/182/max_bus_speed:8.0 GT/s PCIe

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