From: Jeff Kirsher <jeffrey.t.kirsher@intel•com>
To: Jesper Dangaard Brouer <brouer@redhat•com>, netdev@vger•kernel.org
Cc: Alexander Duyck <alexander.duyck@gmail•com>
Subject: Re: [net-next PATCH] ixgbe: add counter for times rx pages gets allocated, not recycled
Date: Fri, 01 Sep 2017 12:09:53 -0700 [thread overview]
Message-ID: <1504292993.3922.25.camel@intel.com> (raw)
In-Reply-To: <150426329512.26774.12697329010993174947.stgit@firesoul>
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On Fri, 2017-09-01 at 12:54 +0200, Jesper Dangaard Brouer wrote:
> The ixgbe driver have page recycle scheme based around the RX-ring
> queue, where a RX page is shared between two packets. Based on the
> refcnt, the driver can determine if the RX-page is currently only
> used
> by a single packet, if so it can then directly refill/recycle the
> RX-slot by with the opposite "side" of the page.
>
> While this is a clever trick, it is hard to determine when this
> recycling is successful and when it fails. Adding a counter, which
> is
> available via ethtool --statistics as 'alloc_rx_page'. Which counts
> the number of times the recycle fails and the real page allocator is
> invoked. When interpreting the stats, do remember that every alloc
> will serve two packets.
>
> The counter is collected per rx_ring, but is summed and ethtool
> exported as 'alloc_rx_page'. It would be relevant to know what
> rx_ring that cannot keep up, but that can be exported later if
> someone experience a need for this.
>
> Signed-off-by: Jesper Dangaard Brouer <brouer@redhat•com>
Since Alex has a suggested change for this patch, when you resubmit v2,
can you make sure you CC intel-wired-lan mailing list, so that my
patchwork project picks up this patch? Thanks in advance Jesper.
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prev parent reply other threads:[~2017-09-01 19:09 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-01 10:54 [net-next PATCH] ixgbe: add counter for times rx pages gets allocated, not recycled Jesper Dangaard Brouer
2017-09-01 15:24 ` Alexander Duyck
2017-09-01 19:09 ` Jeff Kirsher [this message]
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