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[Xen-users] BUG? vif RX/TX byte counters limited to 32-bit values on 64 bit systems

Hi guys,
I recently experienced that ifconfig executed within dom0 wraps around byte counters after reaching the 32-bit max value (2^32) for XEN vif interfaces. Specifically I was able to observe this for a XEN vif interface connected to a HVM domU running FreeBSD 10.0.

This was on a gentoo 64-bit linux dom0 system with kernel 3.17.7 using Xen 4.3.3. It's worth pointing out that ifconfig shows correct (64) bit values for dom0's xenbr0 device (i.e. no wrap-around) - the last ifconfig command showed 51.7 GiB RX traffic.

Also within the connected domU - also a 64-bit system running under FreeBSD - the counters for the xn0 interface (extracted by using the netstat command as ifconfig under FreeBSD does not display counters) are correct and do not reset after reaching the 32-bit upper limit (the values at that time were 29618179358 bytes TX and 18665886357 RX bytes - so well above the 32-bit limit).

As I don't think this is expected behaviour for a 64 bit system and both ifconfig (under linux) and netstat (under FreeBSD) seem to work as expected for (other) interfaces, I suspect there's a bug lurking somewhere in the vif code - probably a 32-bit variable where it should be 64 bit for 64-bit systems.

I wanted to raise this with the user list first before bringing it to the attention of the devs to check whether I am missing something.

Thanks Atom2

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