Messages in this thread | | | Date | Sun, 1 Jun 2008 23:29:08 +0100 | From | Ben Hutchings <> | Subject | Re: [PATCH] net: add ability to clear stats via ethtool - e1000/pcnet32 |
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Bill Fink wrote: > On Sun, 1 Jun 2008, Ben Hutchings wrote: > > > Bill Fink wrote: > > <snip> > > > Yes, every individual Linux network administrator can re-create the > > > wheel by devising their own scripts, but it makes much more sense > > > to me to implement a simple general kernel mechanism once that could > > > be used generically, than to have hundreds (or thousands) of Linux > > > network administrators each having to do it themselves (perhaps > > > multiple times if they have a variety of types of systems and types > > > of NICs). > > > > The ethtool interface is pretty generic, even if the names aren't. > > Here's some Python code I just knocked up which demonstrates how > > to get a set of named stats. It shouldn't be terribly hard to > > extend this to saving and subtracting stat sets. > > I'm not sure what that proves. Your python code just basically gives > the same info as running the "ethtool -S" command.
Yes, but in a form you can more easily manipulate.
> But the question > is how does one devise a generic script or tool that doesn't require > any special knowledge of the specific NIC being used. For example, > here's the "ethtool -S" info for my myri10ge NIC: > > [root@chance8 ~]# ethtool -S eth2 > NIC statistics: [...] > WC: 1 > irq: 8413 > MSI: 1 > read_dma_bw_MBs: 1398 > write_dma_bw_MBs: 1613 > read_write_dma_bw_MBs: 2711 > serial_number: 287046 [...] > tx_linearized: 0 > link_changes: 8 > link_up: 1 [...] > > How does one know which of these reported values are counter stats > that one wishes to zero/snapshot, and which are not?
Ah, I see, I didn't realise some drivers were abusing ethtool stats in this way. But for the most part the differences will show up as zeroes.
If there's really a need for ethtool stats that aren't counters, maybe the ethtool API should include flags to indicate which they are.
> Another issue that occurred to me is if multiple people are working > on troubleshooting a network problem, how do we insure that they all > get a consistent view of the stats? If this is done via a kernel > mechanism then there isn't an issue. But if it's done via user space, > then you have to make sure that everyone zeros/snapshots the stats > at the same time. > > Ideally, one should be able to do something like "ethtool -z ethX" > to zero/snapshot the driver stats, and then "ethtool -S ethX" to get > the stats since the last snapshot. You should be able to use the > same tool ("ethtool") to do all of this, and not some other special > tool or specially devised homegrown script. Why make users lives > any more difficult than need be?
No-one's stopping you from adding these options to ethtool. You could have it save statistic sets in, say, /var/run/ethtool.
Ben.
-- Ben Hutchings, Senior Software Engineer, Solarflare Communications Not speaking for my employer; that's the marketing department's job.
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