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Date:      Tue, 25 Jun 2019 14:40:29 +0200
From:      Christian M <christian.marcos@gmail.com>
To:        Eugene Grosbein <eugen@grosbein.net>
Cc:        freebsd-xen@freebsd.org, freebsd-net@freebsd.org
Subject:   Re: Very slow and inconsistent internal network speed (between, VM's on the same host) for FreeBSD 11.0+ as guest on, XCP-ng/XenServer
Message-ID:  <CAKwR996sPR=qCwk0TO=zhy5J8vOPZtowxFQuK0QooF9bRObOrw@mail.gmail.com>
In-Reply-To: <b0d72766-e7a9-08f7-ed8f-f407fe1285e6@grosbein.net>
References:  <mailman.7.1560945600.15387.freebsd-xen@freebsd.org> <12994df1-f847-ec92-aae8-43a32e59385f@darco.dk> <CAKwR994kQTRfB0R0_WiTYx4pgOHtR-ge7h0vP8NiM_%2B-MBPGGw@mail.gmail.com> <20190625082103.qiiz2cikrauaqlas@MacBook-Air-de-Roger.local> <CAKwR996s9Y_Bea95GOhPkdEJabmJM0r6Qi43gW7_8SXE2ryddA@mail.gmail.com> <b0d72766-e7a9-08f7-ed8f-f407fe1285e6@grosbein.net>

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I've disabled them all on both VM's with FreeBSD 12.0-RELEASE (ifconfig xn0
-txcsum -rxcsum -lro -tso), and also tried disabling everything for the VIF
via XCP-ng earlier. It made no difference unfortunately.

Den tis 25 juni 2019 kl 14:08 skrev Eugene Grosbein <eugen@grosbein.net>:

> 25.06.2019 18:55, Christian M wrote:
>
> > Please note the
> > extremely uneven throughput for test 2 below. It's almost like the
> > throughput increased when running tcpdump simultaneously.
>
> Generally this indicates broken "hardware" offload for some features
> like txcsum/rxcsum/vlan_hwcsum/vlan_hwtagging etc.
>
> Some of them may be automatically disabled while interface is put in
> promiscuous mode
> by running tcpdump and enabled back after tcpdump terminated.
>
> You should look at "options" line in the output of ifconfig for the
> interface
> and manually disable offloads (look for ifconfig(8) manual for details).
> They retry tests without tcpdump running.
>
>



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