On Aug 18 19:05, David Miller wrote: > From: Francois Romieu <rom...@fr.zoreil.com> > Date: Tue, 18 Aug 2015 23:40:17 +0200 > > > Corinna Vinschen <vinsc...@redhat.com> : > >> The r8169 driver collects statistical information returned by > >> @get_stats64 by counting them in the driver itself, even though many > >> (but not all) of the values are already collected by tally counters > >> (TCs) in the NIC. Some of these TC values are not returned by > >> @get_stats64. Especially the received multicast packages are missing > >> from /proc/net/dev. > >> Rectify this by fetching the TCs and returning them from > >> rtl8169_get_stats64. > > > > It is not exactly a some / many / not all / confused [*] picture > > - get_stats64 provides software managed values > > - ethtool provides hardware only values > > > > [*] ok, rx_missed is kinda special. > > > >> The counters collected in the driver obviously disappear as soon as the > >> driver is unloaded so after a driver is loaded the counters always start > >> at 0. The TCs are only reset by a power cycle and there's no known way > >> to reset them programatically. Without further considerations the values > >> collected by the driver would not match up against the TC values. > > > > I'd rather: > > 1. keep software and hardware stats separated > > 2. push to userspace the responsibility to offset device specific hardware > > values jumps > > > > My 0.02 €. > > Any value that is provided by ->get_stats64() should be provided by whatever > mechanism is available and determined to be "prudent" for the device in > question. If the device is not tracking the event, this means pure software > counters. > > If the device tracks the event, you should attempt to use the hardware > facility to provide the ->get_stats64() values. > > If the hardware provides counters not starting at zero on driver load, > one option to handle that is to load the initial values of all of > those counters and calculate diffs at ->get_stats64() time.
That's what my code is doing, just for a limited set of values. I was already wondering why some values available in the hardware tally counters are additionally counted in software. I was planning to propose to use the hardware counters in @get_stats64 in the first place and only count values in the driver which are not provided by the hardware Corinna
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