Date: Mon, 04 May 2015 16:01:28 -0400 From: John Baldwin <jhb@freebsd.org> To: Gleb Smirnoff <glebius@freebsd.org> Cc: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r282280 - in head/sys/dev: e1000 ixgbe ixl Message-ID: <2463555.FfYUgqxYi8@ralph.baldwin.cx> In-Reply-To: <20150504185125.GL34544@FreeBSD.org> References: <201504301823.t3UINd74073186@svn.freebsd.org> <26088556.xbkUe5VAyp@ralph.baldwin.cx> <20150504185125.GL34544@FreeBSD.org>
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On Monday, May 04, 2015 09:51:25 PM Gleb Smirnoff wrote:
> John,
>
> On Mon, May 04, 2015 at 09:58:49AM -0400, John Baldwin wrote:
> J> > J> > J> So the importaing thing here is that if_get_counter() is still doing
> J> > J> > J> per-ifnet stats. The stat you underlined above is per-queue instead.
> J> > J> > J> We well need more explicitly knowledge of queues outside of drivers
> J> > J> > J> and in the stack itself to support a generic framework for per-queue
> J> > J> > J> stats.
> J> > J> >
> J> > J> > This depends on how generic we want the API to be. Of course, we can add
> J> > J> > an extra argument to if_get_counter().
> J> > J> >
> J> > J> > However, if we don't expect the number of queues to exceed a reasonable
> J> > J> > number of 255 :), we can fit the functionality into existing API.
> J> > J> > We can keep the queue number in the highest 8 bits of the ift_counter
> J> > J> > parameter.
> J> > J> >
> J> > J> > #define IFCOUNTER_MASK 0x00ffffff
> J> > J> > #define IFCOUNTER_QUEUE(c) ((c) >> 24)
> J> > J>
> J> > J> I'd prefer that expose queues more directly and figure out how to handle
> J> > J> per-queue stats then (e.g. do we have some sort of driver-independent
> J> > J> structure that each ifnet has 1 or more of that maps to a queue and has
> J> > J> driver provided methods, etc. If so you could have a driver method for
> J> > J> queue stats). Note that I did use if_get_counter to report the
> J> > J> per-interface stats instead of adding a new sysctl.
> J> >
> J> > What do you prefer: an extra argument to the if_get_counter() or a extra
> J> > ifop?
> J>
> J> As I said, I'd prefer we expose queues to the stack more directly complete
> J> with per-queue ops (e.g. I'd like a per-queue if_transmit thing, though
> J> probably more like the old if_start).
>
> Your answer seems quite orthogonal to my question. I reread it couple of times,
> but still can't figure out how exactly do you prefet to fetch per-queue stats.
> Can you please explain in more detail?
struct if_queue {
struct ifnet *ifq_parent;
void (*ifq_get_counter)(struct if_queue *, ift_counter);
...
};
(Pretend that if_queue is a new object type and that each RX or TX queue on a
NIC has one.)
--
John Baldwin
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