Re: waiting on sbwait

From: Danny Braniss (danny_at_cs.huji.ac.il)
Date: 06/24/04

  • Next message: Dan Nelson: "Re: using netgraph to connect 2 physical interfaces into one virtual interface" 
    To: freebsd-hackers@freebsd.org
Date: Thu, 24 Jun 2004 15:41:10 +0300

    >
    > > Danny Braniss wrote:
    > >
    > > >Hi,
    > > > We have a host running samba under -stable 4.10, and quiet frequently
    > > >it becomes uresponsive, hitting ^T gives
    > > >
    > > >load: 0.00 cmd: ls 12807 [sbwait] 0.00u 0.00s 0% 160k
    > > >
    > > >so my guess is that we are running out of some resource (socket buffer).
    > > >
    > > >so, if this is true, is there some sysctl to increase?
    > > >
    > > >danny
    >
    > > I'm not sure if it's what you're hitting, but Perhaps the sysctl
    > > "kern.ipc.maxsockets" needs to be raised, though it seems like you'd
    > > need a decent amount of concurrent active sessions to reach this
    > > ceiling. Also it's read-only, so you'll want to tune it in loader.conf.
    > >
    > > -mpf
    > >
    >
    > sometimes we get
    > load: 0.04 cmd: dmesg 13453 [nfsrcvlk] 0.00u 0.00s 0% 148k
    >
    > and looking through the code, there might be some connection between sbwait
    > and nfsrcvlk, but i doubt that it's sockets that im running out off, neither
    > mbufs, since:
    >
    > foundation> netstat -m
    > 326/1216/26624 mbufs in use (current/peak/max):
    > 326 mbufs allocated to data
    > 321/428/6656 mbuf clusters in use (current/peak/max)
    > 1160 Kbytes allocated to network (5% of mb_map in use)
    > 0 requests for memory denied
    > 0 requests for memory delayed
    > 0 calls to protocol drain routines
    >
    > also, the process enters sbwait either in sosend or soreceive, make me
    > believe that it's some resource, rather than data, that is missing.
    >
    > the fact that this 'unresponsivness' happens sometimes is making this
    > rather challenging, but try to tell this to the users :-)
    >
    > danny

    found the cause: NFS/amd
    a user had several symlinks to /net/host/xyz, and host was down.
    doing ls -F /net/host/xyz does the trick, the machine becomes
    unresponsive.

    now have to look for the reason :-(

    danny

    _______________________________________________
    freebsd-hackers@freebsd.org mailing list
    http://lists.freebsd.org/mailman/listinfo/freebsd-hackers
    To unsubscribe, send any mail to "freebsd-hackers-unsubscribe@freebsd.org"

  • Next message: Dan Nelson: "Re: using netgraph to connect 2 physical interfaces into one virtual interface"