Re: [PATCH 4/5] ib/core: add support for extended performance counters in sysfs

[Or Gerlitz <ogerlitz-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>]

On 11/8/2011 3:09 AM, Jason Gunthorpe wrote:
> Roland Dreier wrote:
>>
>> Let's make sure we learn from our mistakes.  Let's say we create a
>> new "ext_counters" directory.  What should the format of those files
>> be?  Should they be assumed to be 64-bit quantities?  Do we want to
>> allow some way of indicating the number of bits (ie 0-padded hex
>> entries?)?
>
> That is a good idea. Let's require counters_ext to be sane:
>
>   1 Hex quantity of unspecified size
>   2 Prefixed with 0x and leading zeros to fill out to size and allow
>     userspace discovery of size
>   3 Size must be a multiple of 4 bits.
>   4 Counters do not saturate
>   5 Counters wrap around at all F's back to 0.
>   6 If the counter is resettable it is only via a local operation
>     through netlink or sysfs or something. Not PMA reset.
>
> Certainly, aside from some minor details and different string
> formatting, the 64 bit counters Or proposes to add meet these
> requirements when the port is used in Ethernet mode.

Jason, in an earlier post of yours you mentioned the netdev counters as 
something we should be following, well, I took a look - the counters are 
read-only (see /sys/class/net/$DEV/statistics/*) they are displayed in 
decimal/non-padded manner (see /sys/class/net/$DEV/statistics/* or 
/proc/net/dev or ifconfig and friends)

Roland, I'd like to re-format these patches for 3.3, will be glad to 
hear what you would like to see here,

> How do you feel about having counters_ext appear in ethernet mode and
> disappear in IB mode?

I think I'm fine with that, IB has its own MAD based means to query these counters.



Or.

  


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