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Message-ID: <4B56AADA.6030109@jp.fujitsu.com> Date: Wed, 20 Jan 2010 16:03:54 +0900 From: Koki Sanagi <sanagi.koki@...fujitsu.com> To: Yang Hongyang <yanghy@...fujitsu.com> CC: netdev@...r.kernel.org, davem@...emloft.net, nhorman@...driver.com, izumi.taku@...fujitsu.com, kaneshige.kenji@...fujitsu.com Subject: Re: [PATCH 0/5] tracing/events: add tracepoint to TCP/IP stack and netdev layer (2010/01/20 10:41), Yang Hongyang wrote: > Koki Sanagi wrote: >> These patch-set adds some tracepoints to the TCP/IP stack and netdev layer. >> >> As described below, >> http://marc.info/?l=linux-netdev&m=126096487212459&w=2 >> dev_hard_start_xmit and netif_receive_skb are important location to add >> tracepoints. Because driver depends on an machine environment, we usually >> check this point when solving network problem. But these two points are lack of >> infrotmation that what packets are passed, So I add other tracepoints to know >> what packets are passed and to give some merits. >> >> Added tracepoints are at transmit/receive entry of TCP, UDP, RAW, IPv4, driver >> and Qdisc. And tracepoints to output information to make connection >> between these entry tracepoints are also added. >> >> These tracepoints give some merits. >> For example, they enable us to measure packet latency. >> By using tcpdump, we can analyze what packets are passed, but we cannot analyze >> how long it takes to pass through network layer(In other words, latency of TCP >> layer, IP layer and Qdisc). >> Packet latency is very useful information to solve a network bad performance or >> bad reaction network application, packet latency is very useful information. > > If you could point out what the actual problem these tracepoints can solve, > It will be a lot more peruasive. > > And this patch-set contains a lot of tracepoints.Can you figure out what's > the most important?Are these tracepoints really necessary.You could send out > the most important tracepoints instead of sending out all these. > Main purpose of this patch-set is to trace packets without tcpdump. Tcpdump is not fit to run always, because it causes heavy I/O burden(mainly disk). On the other hand, ftrace's I/O burden is nothing. Most important points are netdev_start_xmit and netdev_receive_skb. Because this is pass points for xmit/receive packets. But only these two points, we cannot determine what packets are passed. At least, IP address is needed(ip_output, ip_rcv). Thanks Koki Sanagi >> >> As an other use case, unlike a tcpdump, they are recorded in ftrace buffer >> without IO burden. Only when you need, output recorded information. >> I mean, they are fit to run always. >> >> Details of added tracepoint are below. >> >> skb_clone chase the cloned skb >> senddata_copy_skb copy userdata to skb for transmit >> >> netdev_start_xmit entry of driver's transmit function. >> netdev_receive_skb entry of netstack(receive). >> dev_queue_xmit entry of Qdisc. >> >> ip_queue_xmit entry of IP layer(TCP transmit) >> ip_push_pending_frames entry of IP layer(UDP transmit) >> ip_output entry of IP layer(RAW transmit) >> ip_frag_queue aggregate fragmented packet >> ip_frag_reasm reasemble fragmented packet >> ip_rcv entry of IP layer(receive) >> >> tcp_sendmsg entry of TCP layer(transmit) >> tcp_sendpage entry of TCP layer(transmit) >> tcp_push_pending_frames all data(tcp_sendmsg have) have copied to skb >> tcp_v4_rcv entry of TCP layer(receive) >> >> udp_sendmsg entry of UDP layer(transmit) >> udp_sendpage entry of UDP layer(transmit) >> udp_push_pending_frames all data(udp_sendmsg have) have copied to skb >> udp_rcv entry of UDP layer(receive). >> >> raw_sendmsg entry of RAW layer(transmit). >> raw_rcv entry of RAW layer(receive). >> >> Outputs are below. >> >> TCP send >> netperf-2513 [000] 2603.586818: tcp_sendmsg: sk=f644eac0 len=5000 >> netperf-2513 [000] 2603.586818: senddata_copy_skb: sk=f644eac0 skbaddr=f7159800 len=1416 >> netperf-2513 [000] 2603.586820: senddata_copy_skb: sk=f644eac0 skbaddr=f7159500 len=1448 >> netperf-2513 [000] 2603.586821: senddata_copy_skb: sk=f644eac0 skbaddr=f7158d80 len=1448 >> netperf-2513 [000] 2603.586822: senddata_copy_skb: sk=f644eac0 skbaddr=f7159c80 len=688 >> netperf-2513 [000] 2603.586822: tcp_push_pending_frames: sk=f644eac0 sport=54875 dport=51707 >> tail-2514 [001] 2603.587577: skb_clone: original=f7159800 clone=f71598b4 >> tail-2514 [001] 2603.587578: ip_queue_xmit: skbaddr=f71598b4 saddr=192.168.100.5 daddr=192.168.100.2 >> tail-2514 [001] 2603.587579: ip_output: skbaddr=f71598b4 saddr=192.168.100.5 daddr=192.168.100.2 >> tail-2514 [001] 2603.587579: dev_queue_xmit: dev=eth10 skbaddr=f71598b4 len=1514 >> tail-2514 [001] 2603.587580: netdev_start_xmit: dev=eth10 skbaddr=f71598b4 len=1514 >> tail-2514 [001] 2603.587628: skb_clone: original=f7159500 clone=f71595b4 >> tail-2514 [001] 2603.587629: ip_queue_xmit: skbaddr=f71595b4 saddr=192.168.100.5 daddr=192.168.100.2 >> tail-2514 [001] 2603.587630: ip_output: skbaddr=f71595b4 saddr=192.168.100.5 daddr=192.168.100.2 >> tail-2514 [001] 2603.587631: dev_queue_xmit: dev=eth10 skbaddr=f71595b4 len=1514 >> tail-2514 [001] 2603.587632: netdev_start_xmit: dev=eth10 skbaddr=f71595b4 len=1514 >> tail-2514 [001] 2603.587632: skb_clone: original=f7158d80 clone=f7158e34 >> tail-2514 [001] 2603.587633: ip_queue_xmit: skbaddr=f7158e34 saddr=192.168.100.5 daddr=192.168.100.2 >> tail-2514 [001] 2603.587634: ip_output: skbaddr=f7158e34 saddr=192.168.100.5 daddr=192.168.100.2 >> tail-2514 [001] 2603.587635: dev_queue_xmit: dev=eth10 skbaddr=f7158e34 len=1514 >> tail-2514 [001] 2603.587635: netdev_start_xmit: dev=eth10 skbaddr=f7158e34 len=1514 >> tail-2514 [001] 2603.587685: skb_clone: original=f7159c80 clone=f7159d34 >> tail-2514 [001] 2603.587685: ip_queue_xmit: skbaddr=f7159d34 saddr=192.168.100.5 daddr=192.168.100.2 >> tail-2514 [001] 2603.587687: ip_output: skbaddr=f7159d34 saddr=192.168.100.5 daddr=192.168.100.2 >> tail-2514 [001] 2603.587687: dev_queue_xmit: dev=eth10 skbaddr=f7159d34 len=1514 >> tail-2514 [001] 2603.587688: netdev_start_xmit: dev=eth10 skbaddr=f7159d34 len=1514 >> >> TCP recv >> <idle>-0 [001] 3499.386601: netdev_receive_skb: dev=eth10 skbaddr=f4a88480 len=1500 >> <idle>-0 [001] 3499.386602: ip_rcv: skbaddr=f4a88480 saddr=192.168.100.2 daddr=192.168.100.5 >> <idle>-0 [001] 3499.386604: tcp_v4_rcv: skbaddr=f4a88480 sport=51035 dport=34474 >> <idle>-0 [000] 3499.386619: netdev_receive_skb: dev=eth10 skbaddr=f3c75300 len=1500 >> <idle>-0 [000] 3499.386619: ip_rcv: skbaddr=f3c75300 saddr=192.168.100.2 daddr=192.168.100.5 >> <idle>-0 [000] 3499.386622: tcp_v4_rcv: skbaddr=f3c75300 sport=51035 dport=34474 >> netserver-2519 [000] 3499.386626: skb_copy_datagram_iovec: skbaddr=f4a88480 len=1448 >> netserver-2519 [000] 3499.386628: skb_copy_datagram_iovec: skbaddr=f3c75300 len=1448 >> >> UDP send >> netperf-2506 [001] 2309.073460: udp_sendmsg: sk=f662e6c0 len=5000 >> netperf-2506 [001] 2309.073466: senddata_copy_skb: sk=f662e6c0 skbaddr=f5f65780 len=1472 >> netperf-2506 [001] 2309.073467: senddata_copy_skb: sk=f662e6c0 skbaddr=f5f65000 len=1480 >> netperf-2506 [001] 2309.073468: senddata_copy_skb: sk=f662e6c0 skbaddr=f3decf00 len=1480 >> netperf-2506 [001] 2309.073469: senddata_copy_skb: sk=f662e6c0 skbaddr=f4802840 len=568 >> netperf-2506 [001] 2309.073470: udp_push_pending_frames: sk=f662e6c0 sport=42679 dport=47640 >> netperf-2506 [001] 2309.073470: ip_push_pending_frames: skbaddr=f5f65780 saddr=192.168.100.5 daddr=192.168.100.2 >> netperf-2506 [001] 2309.073471: ip_output: skbaddr=f5f65780 saddr=192.168.100.5 daddr=192.168.100.2 >> netperf-2506 [001] 2309.073472: dev_queue_xmit: dev=eth10 skbaddr=f5f65780 len=1514 >> netperf-2506 [001] 2309.073473: dev_queue_xmit: dev=eth10 skbaddr=f5f65000 len=1514 >> netperf-2506 [001] 2309.073474: dev_queue_xmit: dev=eth10 skbaddr=f3decf00 len=1514 >> netperf-2506 [001] 2309.073474: dev_queue_xmit: dev=eth10 skbaddr=f4802840 len=602 >> <idle>-0 [001] 2309.073615: netdev_start_xmit: dev=eth10 skbaddr=f5f65780 len=1514 >> <idle>-0 [001] 2309.073616: netdev_start_xmit: dev=eth10 skbaddr=f5f65000 len=1514 >> <idle>-0 [000] 2309.073633: netdev_start_xmit: dev=eth10 skbaddr=f3decf00 len=1514 >> <idle>-0 [000] 2309.073633: netdev_start_xmit: dev=eth10 skbaddr=f4802840 len=602 >> >> UDP recv >> <idle>-0 [001] 3671.663678: netdev_receive_skb: dev=eth10 skbaddr=f5f72d80 len=1500 >> <idle>-0 [001] 3671.663678: ip_rcv: skbaddr=f5f72d80 saddr=192.168.100.2 daddr=192.168.100.5 >> <idle>-0 [001] 3671.663680: ip_frag_queue: skbaddr=f5f72d80 prev=(null) >> <idle>-0 [001] 3671.663681: netdev_receive_skb: dev=eth10 skbaddr=f5f6aa80 len=1500 >> <idle>-0 [001] 3671.663681: ip_rcv: skbaddr=f5f6aa80 saddr=192.168.100.2 daddr=192.168.100.5 >> <idle>-0 [001] 3671.663681: ip_frag_queue: skbaddr=f5f6aa80 prev=f5f72d80 >> <idle>-0 [000] 3671.663702: netdev_receive_skb: dev=eth10 skbaddr=f4800840 len=1500 >> <idle>-0 [000] 3671.663703: ip_rcv: skbaddr=f4800840 saddr=192.168.100.2 daddr=192.168.100.5 >> <idle>-0 [000] 3671.663703: ip_frag_queue: skbaddr=f4800840 prev=f5f6aa80 >> <idle>-0 [000] 3671.663704: netdev_receive_skb: dev=eth10 skbaddr=f4a88b40 len=588 >> <idle>-0 [000] 3671.663705: ip_rcv: skbaddr=f4a88b40 saddr=192.168.100.2 daddr=192.168.100.5 >> <idle>-0 [000] 3671.663705: ip_frag_queue: skbaddr=f4a88b40 prev=f4800840 >> <idle>-0 [000] 3671.663706: skb_clone: original=f4a88b40 clone=f5fff480 >> <idle>-0 [000] 3671.663707: kfree_skb: skbaddr=f5f72d80 protocol=2048 location=c0715f1a >> <idle>-0 [000] 3671.663707: ip_frag_reasm: head=f4a88b40 len=1480 >> <idle>-0 [000] 3671.663711: udp_rcv: skbaddr=f4a88b40 sport=57915 dport=37634 >> netserver-2525 [000] 3671.663718: skb_copy_datagram_iovec: skbaddr=f4a88b40 len=5000 >> netserver-2525 [000] 3671.663718: skb_copy_datagram_iovec: skbaddr=f5f6aa80 len=1480 >> netserver-2525 [000] 3671.663719: skb_copy_datagram_iovec: skbaddr=f4800840 len=1480 >> netserver-2525 [000] 3671.663719: skb_copy_datagram_iovec: skbaddr=f5fff480 len=568 >> >> RAW send >> send-2431 [001] 1813.799957: raw_sendmsg: sk=f4a37200 len=1500 >> send-2431 [001] 1813.799959: senddata_copy_skb: sk=f4a37200 skbaddr=f3dec180 len=1500 >> send-2431 [001] 1813.799960: ip_output: skbaddr=f3dec180 saddr=192.168.100.5 daddr=192.168.100.2 >> send-2431 [001] 1813.799960: dev_queue_xmit: dev=eth10 skbaddr=f3dec180 len=1514 >> send-2431 [001] 1813.799961: netdev_start_xmit: dev=eth10 skbaddr=f3dec180 len=1514 >> >> RAW recv >> <idle>-0 [000] 2052.858947: netdev_receive_skb: dev=eth1 skbaddr=f5f66000 len=1500 >> <idle>-0 [000] 2052.858947: ip_rcv: skbaddr=f5f66000 saddr=192.168.101.2 daddr=192.168.101.5 >> <idle>-0 [000] 2052.858951: skb_clone: original=f5f66000 clone=f3e43cc0 >> <idle>-0 [000] 2052.858952: raw_rcv: skbaddr=f3e43cc0 len=1476 >> recv-2499 [001] 2052.858970: skb_copy_datagram_iovec: skbaddr=f3e43cc0 len=1500 >> >> Best Regards, >> Koki Sanagi<sanagi.koki@...fujitsu.com> >> >> -- >> To unsubscribe from this list: send the line "unsubscribe netdev" in >> the body of a message to majordomo@...r.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> >> > > -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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