Date: Sun, 2 Oct 2011 17:50:10 -0700 From: Jack Vogel <jfvogel@gmail.com> To: Arnaud Lacombe <lacombar@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: <CAFOYbckR%2B=5Maoyv5v1u0846q_X2H_k5T8BqYXP459-Qz_Zoaw@mail.gmail.com> In-Reply-To: <CACqU3MWundT7h4xT9SSGzLGDc6QN_6FyOfy=juG4A1NKH0SGMw@mail.gmail.com> References: <4E886A3B.7000502@sepehrs.com> <CAFOYbcnUbdrCYyDdSeYOWVNL_vhH_zA1d5B=mgrkoUijHXj-SQ@mail.gmail.com> <CACqU3MWundT7h4xT9SSGzLGDc6QN_6FyOfy=juG4A1NKH0SGMw@mail.gmail.com>
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There are differences between adapter and LOM, furthermore, someone could toggle the variable on hardware not using it... SO my question stands, I want to know hardware details. Jack On Sun, Oct 2, 2011 at 5:29 PM, Arnaud Lacombe <lacombar@gmail.com> wrote: > 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> > wrote: > > > >> > >> Latest em(4) driver from HEAD seems to have high latency > >> when MSIX is disabled. > >> > >> With MSIX enabled (hw.em.enable_msix=1): > >> > >> # 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=0 ttl=64 time=0.055 ms > >> 64 bytes from 192.168.1.83: icmp_seq=1 ttl=64 time=0.076 ms > >> 64 bytes from 192.168.1.83: icmp_seq=2 ttl=64 time=0.066 ms > >> 64 bytes from 192.168.1.83: icmp_seq=3 ttl=64 time=0.051 ms > >> 64 bytes from 192.168.1.83: icmp_seq=4 ttl=64 time=0.063 ms > >> > >> --- 192.168.1.83 ping statistics --- > >> 5 packets transmitted, 5 packets received, 0.0% packet loss > >> round-trip min/avg/max/stddev = 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=0 ttl=64 time=0.180 ms > >> 64 bytes from 192.168.1.83: icmp_seq=1 ttl=64 time=0.164 ms > >> 64 bytes from 192.168.1.83: icmp_seq=2 ttl=64 time=0.169 ms > >> 64 bytes from 192.168.1.83: icmp_seq=3 ttl=64 time=0.172 ms > >> 64 bytes from 192.168.1.83: icmp_seq=4 ttl=64 time=0.167 ms > >> > >> --- 192.168.1.83 ping statistics --- > >> 5 packets transmitted, 5 packets received, 0.0% packet loss > >> round-trip min/avg/max/stddev = 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: > >> - igb(4) from HEAD: OK. > >> - Stock 7.3-RELEASE: OK. > >> - 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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