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Date:      Tue, 27 Aug 2013 09:52:52 -0500 (CDT)
From:      Bryan Venteicher <bryanv@daemoninthecloset.org>
To:        Harald Schmalzbauer <h.schmalzbauer@omnilan.de>
Cc:        FreeBSD Stable <freebsd-stable@freebsd.org>, current@freebsd.org
Subject:   Re: [CFT] VMware vmxnet3 ethernet driver
Message-ID:  <1428315986.19291.1377615172231.JavaMail.root@daemoninthecloset.org>
In-Reply-To: <521CB7AC.90605@omnilan.de>
References:  <601099152.721.1375661537866.JavaMail.root@daemoninthecloset.org> <5214D37F.5000307@omnilan.de> <1117188271.19176.1377577117350.JavaMail.root@daemoninthecloset.org> <521CB7AC.90605@omnilan.de>

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----- Original Message -----
> Bez=C3=BCglich Bryan Venteicher's Nachricht vom 27.08.2013 06:18 (localti=
me):
>=20
> ...
>=20
> >> It seems if_vmx doesn't support jumbo frames. If I set mtu 9000, I get
> >> =C2=BBvmx0: cannot populate Rx queue 0=C2=AB, I have no problems using=
 jumbo
> >> frames with vmxnet3.
> >>
> > This could fail for two reasons - could not allocate an mbuf cluster,
> > or the call to bus_dmamap_load_mbuf_sg() failed. For the former, you
> > should check vmstat -z. For the later, the behavior of
> > bus_dmamap_load_mbuf_sg()
> > changed between 9.1 and 9.2, and I know it was broken for awhile. I don=
't
> > recall exactly when I fixed it (I think shortly after I made the origin=
al
> > announcement). Could you retry with the files from HEAD @ [1]? Also, th=
ere
> > are new sysctl oids (dev.vmx.X.mbuf_load_failed & dev.vmx.X.mgetcl_fail=
ed)
> > for these errors.
> >
> > I just compiled the driver on 9.2-RC2 with the sources from HEAD and wa=
s
> > able to change the MTU to 9000.
> >
> > [1]- http://svnweb.freebsd.org/base/head/sys/dev/vmware/vmxnet3/
>=20
> Thanks a lot for your ongoing work!
> I can confirm that with recent if_vmx.c from head and compiled for
> 9.2-RC3, setting mtu to 9000 works as expected :-)
>=20
>=20
> >> I took a oldish host (4x2,8GHz Core2[LGA775]) with recent software: ES=
Xi
> >> 5.1U1 and FreeBSD-9.2-RC2
> >> Two guests are connected to one MTU9000 "VMware Software Switch".
> >>
> > I've got a few performance things to still look at. What's the sysctl
> > dev.vmx.X output for the if_vmx<->if_vmx tests?
>=20
> Just repeated if_vmx simple iperf bench, results vary slightly from
> standard 10sec run to run, but still noticable high Intr usage:
>

The intr usage is higher than the other drivers you compared against
because if_vmx does the off-level processing in ithreads where as the
others do it in a taskqueue.

BTW: if_vmx can to LRO as well. I don't think the emulated e1000 can,
but I bet the e1000e does.

> if_vmx <-> if_vmx
>     1.32 GBits/sec, load: 10-45%Sys 40-48%Intr
>=20
> if_vmxJumbo <-> if_vmxJumbo
>     5.01 GBits/sec, load: 10-45%Sys 40-48%Intr
>=20
> Please find attached the different outputs of dev.vmx.X (the mtu9000 run =
was
> only 3.47GBits/sec in that case, took the numbers anyway)
>=20
> wbr,
>=20
> -Harry
>=20
>=20



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