Date: Sun, 2 Oct 2011 20:29:43 -0400 From: Arnaud Lacombe <lacombar@gmail.com> To: Jack Vogel <jfvogel@gmail.com> Cc: "freebsd-net@freebsd.org" <freebsd-net@freebsd.org>, Hooman Fazaeli <fazaeli@sepehrs.com> Subject: Re: em(4) high latency w/o msix Message-ID: <CACqU3MWundT7h4xT9SSGzLGDc6QN_6FyOfy=juG4A1NKH0SGMw@mail.gmail.com> In-Reply-To: <CAFOYbcnUbdrCYyDdSeYOWVNL_vhH_zA1d5B=mgrkoUijHXj-SQ@mail.gmail.com> References: <4E886A3B.7000502@sepehrs.com> <CAFOYbcnUbdrCYyDdSeYOWVNL_vhH_zA1d5B=mgrkoUijHXj-SQ@mail.gmail.com>
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Hi, On Sun, Oct 2, 2011 at 12:08 PM, Jack Vogel <jfvogel@gmail.com> wrote: > On what hardware? > Only the 82574 is using em(4)'s MSI-X. - Arnaud > Jack > > > On Sun, Oct 2, 2011 at 6:42 AM, Hooman Fazaeli <fazaeli@sepehrs.com> wrot= e: > >> >> Latest em(4) driver from HEAD seems to have high latency >> when MSIX is disabled. >> >> With MSIX enabled (hw.em.enable_msix=3D1): >> >> # ping -c5 192.168.1.83 >> PING 192.168.1.83 (192.168.1.83): 56 data bytes >> 64 bytes from 192.168.1.83: icmp_seq=3D0 ttl=3D64 time=3D0.055 ms >> 64 bytes from 192.168.1.83: icmp_seq=3D1 ttl=3D64 time=3D0.076 ms >> 64 bytes from 192.168.1.83: icmp_seq=3D2 ttl=3D64 time=3D0.066 ms >> 64 bytes from 192.168.1.83: icmp_seq=3D3 ttl=3D64 time=3D0.051 ms >> 64 bytes from 192.168.1.83: icmp_seq=3D4 ttl=3D64 time=3D0.063 ms >> >> --- 192.168.1.83 ping statistics --- >> 5 packets transmitted, 5 packets received, 0.0% packet loss >> round-trip min/avg/max/stddev =3D 0.051/0.062/0.076/0.009 ms >> >> With MSIX disabled: >> >> # ping -c5 192.168.1.83 >> PING 192.168.1.83 (192.168.1.83): 56 data bytes >> 64 bytes from 192.168.1.83: icmp_seq=3D0 ttl=3D64 time=3D0.180 ms >> 64 bytes from 192.168.1.83: icmp_seq=3D1 ttl=3D64 time=3D0.164 ms >> 64 bytes from 192.168.1.83: icmp_seq=3D2 ttl=3D64 time=3D0.169 ms >> 64 bytes from 192.168.1.83: icmp_seq=3D3 ttl=3D64 time=3D0.172 ms >> 64 bytes from 192.168.1.83: icmp_seq=3D4 ttl=3D64 time=3D0.167 ms >> >> --- 192.168.1.83 ping statistics --- >> 5 packets transmitted, 5 packets received, 0.0% packet loss >> round-trip min/avg/max/stddev =3D 0.164/0.170/0.180/0.005 ms >> >> As you see, w/o MSIX, RTT increases by a factor of 3. >> >> I also tested the following drivers: >> =A0 =A0- igb(4) from HEAD: OK. >> =A0 =A0- Stock 7.3-RELEASE: OK. >> =A0 =A0- Stock 7.4-RELEASE: problem exist. >> >> Any ideas? >> >> >> >> >> > _______________________________________________ > freebsd-net@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-net > To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org" >
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