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Date:      Mon, 4 May 2015 21:51:25 +0300
From:      Gleb Smirnoff <glebius@FreeBSD.org>
To:        John Baldwin <jhb@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:  <20150504185125.GL34544@FreeBSD.org>
In-Reply-To: <26088556.xbkUe5VAyp@ralph.baldwin.cx>
References:  <201504301823.t3UINd74073186@svn.freebsd.org> <2197979.EUYqekgM4M@ralph.baldwin.cx> <20150502191000.GE546@FreeBSD.org> <26088556.xbkUe5VAyp@ralph.baldwin.cx>

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  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?

-- 
Totus tuus, Glebius.



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