Date: Tue, 17 Nov 2009 03:29:03 +0300 From: pluknet <pluknet@gmail.com> To: Attilio Rao <attilio@freebsd.org> Cc: pyunyh@gmail.com, freebsd-net@freebsd.org, Bruce Evans <bde@freebsd.org>, John Baldwin <jhb@freebsd.org> Subject: Re: [PATCH] Add idrop report to netstat Message-ID: <a31046fc0911161629h43a4dbcs6809b69e889f2347@mail.gmail.com> In-Reply-To: <3bbf2fe10911161556h6fb602a6qe5043fea590e7800@mail.gmail.com> References: <3bbf2fe10911160715m34fc0ba4hc13af02541405491@mail.gmail.com> <20091116182423.GD1262@michelle.cdnetworks.com> <3bbf2fe10911161404s4c5870a4pe0afbb890e0fdde2@mail.gmail.com> <20091116233828.GG1262@michelle.cdnetworks.com> <3bbf2fe10911161556h6fb602a6qe5043fea590e7800@mail.gmail.com>
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2009/11/17 Attilio Rao <attilio@freebsd.org>: > 2009/11/17 Pyun YongHyeon <pyunyh@gmail.com>: >> On Mon, Nov 16, 2009 at 11:04:20PM +0100, Attilio Rao wrote: >>> 2009/11/16 Pyun YongHyeon <pyunyh@gmail.com>: >>> > On Mon, Nov 16, 2009 at 04:15:09PM +0100, Attilio Rao wrote: >>> >> [Please CC me as I'm not subscribed to -net@] >>> >> >>> >> This patch allows to show the informations about packets droped on >>> >> input for interfaces on netstat: >>> >> http://www.freebsd.org/~attilio/Sandvine/STABLE_8/idrops/idrops.diff >>> >> >>> >> This patch as been contributed back from Sandvine Incorporated. >>> >> Comments, reviews and testing are welcome. >>> >> >>> > >>> > Doesn't -d of netstat(1) show the same information? >>> >>> Am I wrong or "-d" prints the drops on the output path? >>> The patch provides information on the input drops. >>> >> >> struct if_data { >> /* generic interface information */ >> u_char ifi_type; /* ethernet, tokenring, etc */ >> u_char ifi_physical; /* e.g., AUI, Thinnet, 10base-T, etc */ >> [...] >> u_long ifi_iqdrops; /* dropped on input, this interface */ >> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ >> >> u_long ifi_noproto; /* destined for unsupported protocol */ >> u_long ifi_hwassist; /* HW offload capabilities, see IFCAP */ >> time_t ifi_epoch; /* uptime at attach or stat reset */ >> struct timeval ifi_lastchange; /* time of last administrative change */ >> }; > > Err, but dflag does print out if_snd.ifq_drops. Infact: > > @if.c:sidewaysintpr() > > [...] > if (!first) { > show_stat("lu", 10, ifnet.if_ipackets - ip->ift_ip, 1); > show_stat("lu", 5, ifnet.if_ierrors - ip->ift_ie, 1); > show_stat("lu", 10, ifnet.if_ibytes - ip->ift_ib, 1); > show_stat("lu", 10, ifnet.if_opackets - ip->ift_op, 1); > show_stat("lu", 5, ifnet.if_oerrors - ip->ift_oe, 1); > show_stat("lu", 10, ifnet.if_obytes - ip->ift_ob, 1); > show_stat("NRSlu", 5, > ifnet.if_collisions - ip->ift_co, 1); > if (dflag) > show_stat("LSu", 5, > ifnet.if_snd.ifq_drops - ip->ift_dr, 1); > } > [...] > if (!first) { > show_stat("lu", 10, sum->ift_ip - total->ift_ip, 1); > show_stat("lu", 5, sum->ift_ie - total->ift_ie, 1); > show_stat("lu", 10, sum->ift_ib - total->ift_ib, 1); > show_stat("lu", 10, sum->ift_op - total->ift_op, 1); > show_stat("lu", 5, sum->ift_oe - total->ift_oe, 1); > show_stat("lu", 10, sum->ift_ob - total->ift_ob, 1); > show_stat("NRSlu", 5, sum->ift_co - total->ift_co, 1); > if (dflag) > show_stat("LSu", 5, > sum->ift_dr - total->ift_dr, 1); > } > > > Which is defined in sys/net/if_var.h as: > > struct ifnet { > void *if_softc; /* pointer to driver state */ > void *if_l2com; /* pointer to protocol bits */ > struct vnet *if_vnet; /* pointer to network stack instance */ > [...] > int if_drv_flags; /* driver-managed status flags */ > struct ifaltq if_snd; /* output queue (includes altq) */ > const u_int8_t *if_broadcastaddr; /* linklevel broadcast bytestring */ > [...] > }; ifq_drops != *_iqdrops Historically *_iqdrops was designed strictly to record falure to allocate a buffer on Rx chain (or so). while ifq_drops was for logically higher level: output and (some kind of) input ifnet queue shortage stats. [and that's recorded in the earlier BSD's. Though, input queue was replaced later with netisr magics in if_ethersubr.c, though it still possible to track the roots in struct netist_work{ nw_len..nw_qlimit..nw_drops }). -- wbr, pluknet
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