37 lines
1.2 KiB
Plaintext
37 lines
1.2 KiB
Plaintext
Demonstrations of tcpsynbl, the Linux BCC/eBPF version.
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This tool shows the TCP SYN backlog size during SYN arrival as a histogram.
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This lets you see how close your applications are to hitting the backlog limit
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and dropping SYNs (causing performance issues with SYN retransmits). For
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example:
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# ./tcpsynbl.py
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Tracing SYN backlog size. Ctrl-C to end.
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^C
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backlog_max = 500L
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backlog : count distribution
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0 -> 1 : 961 |****************************************|
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2 -> 3 : 1 | |
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This output shows that for the backlog limit of 500, there were 961 SYN
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arrival where the backlog was zero or one, and one accept where the backlog was
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two or three. This indicates that we are nowhere near this limit.
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USAGE:
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# ./tcpsynbl -h
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usage: tcpsynbl.py [-h] [-4 | -6]
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Show TCP SYN backlog.
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optional arguments:
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-h, --help show this help message and exit
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-4, --ipv4 trace IPv4 family only
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-6, --ipv6 trace IPv6 family only
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examples:
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./tcpsynbl # trace syn backlog
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./tcpsynbl -4 # trace IPv4 family only
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./tcpsynbl -6 # trace IPv6 family only |