unimore/kernel-hacking-2024-linux-steffo
unimore/kernel-hacking-2024-linux-steffo
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Stanislav Fomichev 395338843d samples/bpf: add sample program that periodically dumps TCP stats 
Uses new RTT callback to dump stats every second.

$ mkdir -p /tmp/cgroupv2
$ mount -t cgroup2 none /tmp/cgroupv2
$ mkdir -p /tmp/cgroupv2/foo
$ echo $$ >> /tmp/cgroupv2/foo/cgroup.procs
$ bpftool prog load ./tcp_dumpstats_kern.o /sys/fs/bpf/tcp_prog
$ bpftool cgroup attach /tmp/cgroupv2/foo sock_ops pinned /sys/fs/bpf/tcp_prog
$ bpftool prog tracelog
$ # run neper/netperf/etc

Used neper to compare performance with and without this program attached
and didn't see any noticeable performance impact.

Sample output:
  <idle>-0     [015] ..s.  2074.128800: 0: dsack_dups=0 delivered=242526
  <idle>-0     [015] ..s.  2074.128808: 0: delivered_ce=0 icsk_retransmits=0
  <idle>-0     [015] ..s.  2075.130133: 0: dsack_dups=0 delivered=323599
  <idle>-0     [015] ..s.  2075.130138: 0: delivered_ce=0 icsk_retransmits=0
  <idle>-0     [005] .Ns.  2076.131440: 0: dsack_dups=0 delivered=404648
  <idle>-0     [005] .Ns.  2076.131447: 0: delivered_ce=0 icsk_retransmits=0

Cc: Eric Dumazet <edumazet@google.com>
Cc: Priyaranjan Jha <priyarjha@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: Soheil Hassas Yeganeh <soheil@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Acked-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-07-03 16:52:02 +02:00
..
auxdisplay auxdisplay: Replace licenses with SPDX identifiers 2018-04-12 19:02:45 +02:00
binderfs treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
bpf samples/bpf: add sample program that periodically dumps TCP stats 2019-07-03 16:52:02 +02:00
configfs treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 145 2019-05-30 11:25:18 -07:00
connector treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
hidraw HID: samples/hidraw: fix typo in printed message 2018-11-21 00:31:58 +01:00
hw_breakpoint treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
kdb treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
kfifo treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 465 2019-06-19 17:09:10 +02:00
kobject treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
kprobes treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
livepatch treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 13 2019-05-21 11:28:45 +02:00
mei samples: mei: use /dev/mei0 instead of /dev/mei 2019-01-30 15:24:45 +01:00
mic/mpssd treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 290 2019-06-05 17:36:38 +02:00
pidfd samples: fix pidfd-metadata compilation 2019-06-05 15:06:07 +02:00
pktgen Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-11-04 09:26:51 +09:00
qmi treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
rpmsg treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 282 2019-06-05 17:36:37 +02:00
seccomp samples: guard sub-directories with CONFIG options 2019-05-18 11:29:01 +09:00
timers License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
trace_events treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
trace_printk treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
uhid treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
v4l treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
vfio-mdev treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
vfs treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 36 2019-05-24 17:27:11 +02:00
watchdog License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
Kconfig treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
Makefile samples: guard sub-directories with CONFIG options 2019-05-18 11:29:01 +09:00