From: "Michał Niciejewski" <michal.niciejewski@codilime.com>
To: "Van Haaren, Harry" <harry.van.haaren@intel.com>
Cc: "users@dpdk.org" <users@dpdk.org>
Subject: Re: Unexpected behavior when using mbuf pool with external buffers
Date: Wed, 22 Dec 2021 17:30:24 +0100 [thread overview]
Message-ID: <CA+xtTg1wo2icBR=WkfwFtGHCUQwC1oCPu5EWPe=4QDoEnZCGGQ@mail.gmail.com> (raw)
In-Reply-To: <BN0PR11MB5712E89AFD4C830E58D1DC31D77D9@BN0PR11MB5712.namprd11.prod.outlook.com>
Thank you for the replay,
On Wed, Dec 22, 2021 at 11:24 AM Van Haaren, Harry
<harry.van.haaren@intel.com> wrote:
> I'll "top post" on this reply as the content is in HTML format below. In future, please try to send plain-text emails to DPDK mailing lists.
I hope it's better now.
> Estimating and talking is never conclusive – lets measure using Linux "Perf" tool. Run this command 3x, just like you posted the drop stats below.
>
> I expect to see lower dTLB-load-misses on the first run (no drops, 10 mpps), and that the dTLB misses are higher for 15 mpps *and* for 10 mpps again afterwards.
>
> perf stat -e cycles,dTLB-load-misses -C <datapath_lcore_here> -- sleep 1
extbuf, aligned_alloc, 10mpps, first run
Performance counter stats for 'CPU(s) 0':
2404553948 cycles
461 dTLB-load-misses
1.001938861 seconds time elapsed
extbuf, aligned_alloc, 15mpps
Performance counter stats for 'CPU(s) 0':
2404518710 cycles
466 dTLB-load-misses
1.001920171 seconds time elapsed
extbuf, aligned_alloc, 10mpps, second run
Performance counter stats for 'CPU(s) 0':
2402586106 cycles
449 dTLB-load-misses
1.001114692 seconds time elapsed
I also checked what happens when there is no traffic at all and the
results are similar:
Performance counter stats for 'CPU(s) 0':
2949935339 cycles
465 dTLB-load-misses
1.002236168 seconds time elapsed
Also, I checked how the application behaves when adding --no-huge
option and using a normal mbuf pool. The results are very different
compared to aligned_alloc + extbuf mbuf pool:
10mpps, --no-huge
Performance counter stats for 'CPU(s) 0':
2402616160 cycles
17980033 dTLB-load-misses
1.001125954 seconds time elapsed
Application logs:
Queue: 0
Number of all rx burst calls: 5757205
Number of non-zero rx burst calls: 1073081
Avg pkt nb received per rx burst: 1.7364
All received pkts: 9996804
All sent pkts: 8074460
All dropped pkts: 1922344
--
Michał Niciejewski
Junior Software Engineer
michal.niciejewski@codilime.com
CodiLime Sp. z o.o. - Ltd. company with its registered office in
Poland, 02-493 Warsaw, ul. Krancowa 5.
Registered by The District Court for the Capital City of Warsaw, XII
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next prev parent reply other threads:[~2021-12-22 16:30 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-22 9:56 Michał Niciejewski
2021-12-22 10:24 ` Van Haaren, Harry
2021-12-22 16:30 ` Michał Niciejewski [this message]
2022-01-18 13:41 ` Michał Niciejewski
2021-12-22 12:28 ` Gábor LENCSE
-- strict thread matches above, loose matches on Subject: below --
2021-12-21 11:48 Michał Niciejewski
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