Date: Tue, 23 Sep 2014 22:22:51 +0200 From: Hans Petter Selasky <hps@selasky.org> To: Gleb Smirnoff <glebius@FreeBSD.org> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r272027 - in head: contrib/ofed/libibverbs/examples contrib/ofed/libmlx4/src sys/conf sys/modules/mlx4 sys/modules/mlxen sys/ofed/drivers/infiniband/hw/mlx4 sys/ofed/drivers/infiniband/... Message-ID: <5421D69B.3000206@selasky.org> In-Reply-To: <20140923182549.GG884@FreeBSD.org> References: <201409231237.s8NCb27N061223@svn.freebsd.org> <20140923182549.GG884@FreeBSD.org>
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On 09/23/14 20:25, Gleb Smirnoff wrote: > Hans, > > On Tue, Sep 23, 2014 at 12:37:02PM +0000, Hans Petter Selasky wrote: > H> Author: hselasky > H> Date: Tue Sep 23 12:37:01 2014 > H> New Revision: 272027 > H> URL: http://svnweb.freebsd.org/changeset/base/272027 > H> > H> Log: > H> Hardware driver update from Mellanox Technologies, including: > H> - improved performance > H> - better stability > H> - new features > H> - bugfixes > ... > H> @@ -240,7 +240,7 @@ ipoib_ib_handle_rx_wc(struct ipoib_dev_p > H> */ > H> if (unlikely(!ipoib_alloc_rx_mb(priv, wr_id))) { > H> memcpy(&priv->rx_ring[wr_id], &saverx, sizeof(saverx)); > H> - dev->if_iqdrops++; > H> + if_inc_counter(dev, IFCOUNTER_IQDROPS, 1); > H> goto repost; > H> } > > Thanks a lot for these changes :) > > However, to fully convert driver to new stats we need to 1) stop > writing to ifnet if_foo fields, 2) provide if_get_counter() method, > that will return current counter values. > > This can be achieved in two ways: > > 1) Dumb solution. Remove assignments for if_foo counters from > mlx4_en_DUMP_ETH_STATS(). Provide if_get_counter() method, that will > return the values using the same code we deleted. > The cons of the solution is that we still run a useless callout > to gather statistics, and that statistics are updated only on callout. > If we query the interface faster than 1 time per second, we will get > same results in two queries. > > Example of dumb solution can be found in igb(4). > > Since the code is shared between OSes, it could be that dumb solution > is the best, since it is less disruptive. > > 2) Smarter solution. Remove assignments for if_foo counters from > mlx4_en_DUMP_ETH_STATS(). Do not run mlx4_en_DUMP_ETH_STATS() periodically. > Provide if_get_counter() method, that will first run mlx4_en_DUMP_ETH_STATS(), > and then do a switch on counter type and return it. > > Example of smarter solution is vtnet(4). > > 3) Smart solution. Remove assignments for if_foo counters from > mlx4_en_DUMP_ETH_STATS(). Do not run mlx4_en_DUMP_ETH_STATS() periodically. > Provide if_get_counter() method, that will switch on the counter type > and query the proper hardware register to fetch the value and return it. > > No examples available, yet :) > > Can you help me with this, please? I can code the dumb one quickly, but > probably committing it w/o hardware test is a risky plan. > Hi Gleb, I can give you a hand on this. It's currently late where I am, and I will look into this tomorrow. Thank you! --HPS
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