From: Jesper Dangaard Brouer <brouer@redhat.com>
To: Mel Gorman <mgorman@techsingularity.net>,
linux-mm <linux-mm@kvack.org>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
Brenden Blanco <bblanco@plumgrid.com>
Cc: brouer@redhat.com, tom@herbertland.com,
alexei.starovoitov@gmail.com, ogerlitz@mellanox.com,
daniel@iogearbox.netbrouer@redhat.com, eric.dumazet@gmail.com,
ecree@solarflare.com, john.fastabend@gmail.com, tgraf@suug.ch,
johannes@sipsolutions.net, eranlinuxmellanox@gmail.com
Subject: FlameGraph of mlx4 early drop with order-0 pages
Date: Fri, 15 Apr 2016 21:40:34 +0200 [thread overview]
Message-ID: <20160415214034.6ffae9ee@redhat.com> (raw)
Hi Mel,
I did an experiment that you might find interesting. Using Brenden's
early drop with eBPF in the mxl4 driver. I changed the mlx4 driver to
use order-0 pages. It usually use order-3 pages to amortize the cost
of calling the page allocator (which is problematic for other reasons,
like memory pin-down, latency spikes and multi CPU scalability)
With this change I could do around 12Mpps (Mill packet per sec) drops,
usually does 14.5Mpps (limited due to a HW setup/limit, with idle cycles).
Looking at the perf report as a FlameGraph, the page allocator clearly
show up as the bottleneck:
http://people.netfilter.org/hawk/FlameGraph/flamegraph-mlx4-order0-pages-eBPF-XDP-drop.svg
Signing off, heading for the plane soon... see you at MM-summit!
--
Best regards,
Jesper Dangaard Brouer
MSc.CS, Principal Kernel Engineer at Red Hat
Author of http://www.iptv-analyzer.org
LinkedIn: http://www.linkedin.com/in/brouer
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next reply other threads:[~2016-04-15 19:40 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-15 19:40 Jesper Dangaard Brouer [this message]
2016-04-17 13:23 ` FlameGraph of mlx4 early drop with order-0 pages Mel Gorman
2016-04-17 17:24 ` Jesper Dangaard Brouer
2016-04-17 17:52 ` Mel Gorman
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