Current File : //usr/share/doc/bpftrace/examples/tcpdrop_example.txt
Demonstrations of tcpdrop, the Linux bpftrace/eBPF version.
tcpdrop prints details of TCP packets or segments that were dropped by the
kernel, including the kernel stack trace that led to the drop:
# ./tcpdrop.bt
TIME PID COMM SADDR:SPORT DADDR:DPORT STATE
00:39:21 0 swapper/2 10.231.244.31:3306 10.229.20.82:50552 ESTABLISHE
tcp_drop+0x1
tcp_v4_do_rcv+0x135
tcp_v4_rcv+0x9c7
ip_local_deliver_finish+0x62
ip_local_deliver+0x6f
ip_rcv_finish+0x129
ip_rcv+0x28f
__netif_receive_skb_core+0x432
__netif_receive_skb+0x18
netif_receive_skb_internal+0x37
napi_gro_receive+0xc5
ena_clean_rx_irq+0x3c3
ena_io_poll+0x33f
net_rx_action+0x140
__softirqentry_text_start+0xdf
irq_exit+0xb6
do_IRQ+0x82
ret_from_intr+0x0
native_safe_halt+0x6
default_idle+0x20
arch_cpu_idle+0x15
default_idle_call+0x23
do_idle+0x17f
cpu_startup_entry+0x73
rest_init+0xae
start_kernel+0x4dc
x86_64_start_reservations+0x24
x86_64_start_kernel+0x74
secondary_startup_64+0xa5
[...]
The last column shows the state of the TCP session.
This tool is useful for debugging high rates of drops, which can cause the
remote end to do timer-based retransmits, hurting performance.
USAGE:
# ./tcpdrop.bt
Mini Shell