Date: Fri, 11 Apr 2003 19:09:21 +0200 From: Borje Josefsson <bj@dc.luth.se> To: Terry Lambert <tlambert2@mindspring.com> Cc: David Gilbert <dgilbert@velocet.ca> Subject: Re: tcp_output starving -- is due to mbuf get delay? Message-ID: <200304111709.h3BH9LKl087299@dc.luth.se> In-Reply-To: Your message of Fri, 11 Apr 2003 09:32:51 PDT. <3E96EE33.FAF4FABB@mindspring.com>
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On Fri, 11 Apr 2003 09:32:51 PDT Terry Lambert wrote:
> See other posting; I listed a bunch of OIDs to play with.
> =
> One other, if you are running -CURRENT, would be:
> =
> net.isr.netisr_enable -> 1
I'm running 4.8RC on the sender right now.
I did a quick test with some combination of the OID:s You sent, except I =
didn't reboot between each test:
> Some knobs to try on FreeBSD:
>
> net.inet.ip.intr_queue_maxlen -> 300
> net.inet.ip.check_interface -> 0
> net.inet.tcp.rfc1323 -> 0
> net.inet.tcp.inflight_enable -> 1
> net.inet.tcp.inflight_debug -> 0
> net.inet.tcp.delayed_ack -> 0
> net.inet.tcp.newreno -> 0
> net.inet.tcp.slowstart_flightsize -> 4
> net.inet.tcp.msl -> 1000
> net.inet.tcp.always_keepalive -> 0
> net.inet.tcp.sendspace -> 65536 (on sender)
I didn't test all combinations, but all of them give the same result (~57=
0 =
Mbit/sec, and I run out of CPU), except inflight_enable, which =
*considerably* lowers the performance.I get around 570 Mbit/sec, and run =
out of CPU.
Netstat -m (tcp and ip portion) when I started and after the trials:
=3D=3D=3D before =3D=3D=3D
tcp:
12103350 packets sent
2692690 data packets (1962127658 bytes)
10203 data packets (14829100 bytes) retransmitted
0 resends initiated by MTU discovery
6446084 ack-only packets (199 delayed)
0 URG only packets
0 window probe packets
2955524 window update packets
216 control packets
16306846 packets received
847040 acks (for 1962119767 bytes)
14399 duplicate acks
0 acks for unsent data
15281399 packets (2057886406 bytes) received in-sequence
4425 completely duplicate packets (4551322 bytes)
0 old duplicate packets
65 packets with some dup. data (14957 bytes duped)
38818 out-of-order packets (59514384 bytes)
0 packets (0 bytes) of data after window
0 window probes
120161 window update packets
3 packets received after close
4 discarded for bad checksums
0 discarded for bad header offset fields
0 discarded because packet too short
160 connection requests
49 connection accepts
0 bad connection attempts
0 listen queue overflows
63 connections established (including accepts)
383 connections closed (including 5 drops)
10 connections updated cached RTT on close
10 connections updated cached RTT variance on close
2 connections updated cached ssthresh on close
146 embryonic connections dropped
846952 segments updated rtt (of 521492 attempts)
36 retransmit timeouts
2 connections dropped by rexmit timeout
0 persist timeouts
0 connections dropped by persist timeout
438 keepalive timeouts
438 keepalive probes sent
0 connections dropped by keepalive
26449 correct ACK header predictions
15280149 correct data packet header predictions
49 syncache entries added
0 retransmitted
0 dupsyn
0 dropped
49 completed
0 bucket overflow
0 cache overflow
0 reset
0 stale
0 aborted
0 badack
0 unreach
0 zone failures
0 cookies sent
0 cookies received
ip:
16393480 total packets received
0 bad header checksums
0 with size smaller than minimum
0 with data size < data length
0 with ip length > max ip packet size
0 with header length < data size
0 with data length < header length
0 with bad options
0 with incorrect version number
1 fragment received
0 fragments dropped (dup or out of space)
1 fragment dropped after timeout
0 packets reassembled ok
16393029 packets for this host
450 packets for unknown/unsupported protocol
0 packets forwarded (0 packets fast forwarded)
0 packets not forwardable
0 packets received for unknown multicast group
0 redirects sent
12201936 packets sent from this host
115 packets sent with fabricated ip header
1367 output packets dropped due to no bufs, etc.
0 output packets discarded due to no route
0 output datagrams fragmented
0 fragments created
0 datagrams that can't be fragmented
0 tunneling packets that can't find gif
0 datagrams with bad address in header
=3D=3D=3D=3D after =3D=3D=3D=3D
tcp:
13331442 packets sent
3920701 data packets (2694929130 bytes)
10203 data packets (14829100 bytes) retransmitted
0 resends initiated by MTU discovery
6446155 ack-only packets (207 delayed)
0 URG only packets
0 window probe packets
2955524 window update packets
226 control packets
17131926 packets received
1526734 acks (for 2694921244 bytes)
14404 duplicate acks
0 acks for unsent data
15281806 packets (2057905910 bytes) received in-sequence
4425 completely duplicate packets (4551322 bytes)
0 old duplicate packets
65 packets with some dup. data (14957 bytes duped)
38818 out-of-order packets (59514384 bytes)
0 packets (0 bytes) of data after window
0 window probes
265251 window update packets
3 packets received after close
4 discarded for bad checksums
0 discarded for bad header offset fields
0 discarded because packet too short
165 connection requests
49 connection accepts
0 bad connection attempts
0 listen queue overflows
68 connections established (including accepts)
388 connections closed (including 5 drops)
15 connections updated cached RTT on close
15 connections updated cached RTT variance on close
2 connections updated cached ssthresh on close
146 embryonic connections dropped
1526646 segments updated rtt (of 793534 attempts)
36 retransmit timeouts
2 connections dropped by rexmit timeout
0 persist timeouts
0 connections dropped by persist timeout
438 keepalive timeouts
438 keepalive probes sent
0 connections dropped by keepalive
79056 correct ACK header predictions
15280431 correct data packet header predictions
49 syncache entries added
0 retransmitted
0 dupsyn
0 dropped
49 completed
0 bucket overflow
0 cache overflow
0 reset
0 stale
0 aborted
0 badack
0 unreach
0 zone failures
0 cookies sent
0 cookies received
ip:
17218567 total packets received
0 bad header checksums
0 with size smaller than minimum
0 with data size < data length
0 with ip length > max ip packet size
0 with header length < data size
0 with data length < header length
0 with bad options
0 with incorrect version number
1 fragment received
0 fragments dropped (dup or out of space)
1 fragment dropped after timeout
0 packets reassembled ok
17218116 packets for this host
450 packets for unknown/unsupported protocol
0 packets forwarded (0 packets fast forwarded)
0 packets not forwardable
0 packets received for unknown multicast group
0 redirects sent
13430039 packets sent from this host
115 packets sent with fabricated ip header
1367 output packets dropped due to no bufs, etc.
0 output packets discarded due to no route
0 output datagrams fragmented
0 fragments created
0 datagrams that can't be fragmented
0 tunneling packets that can't find gif
0 datagrams with bad address in header
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