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67 lines
1.4 KiB
67 lines
1.4 KiB
#!/usr/bin/env python
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#
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# vfsreadlat.py VFS read latency distribution.
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# For Linux, uses BCC, eBPF. See .c file.
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#
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# Written as a basic example of a function latency distribution histogram.
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#
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# USAGE: vfsreadlat.py [interval [count]]
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#
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# The default interval is 5 seconds. A Ctrl-C will print the partially
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# gathered histogram then exit.
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#
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# Copyright (c) 2015 Brendan Gregg.
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# Licensed under the Apache License, Version 2.0 (the "License")
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#
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# 15-Aug-2015 Brendan Gregg Created this.
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from __future__ import print_function
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from bcc import BPF
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from ctypes import c_ushort, c_int, c_ulonglong
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from time import sleep
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from sys import argv
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def usage():
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print("USAGE: %s [interval [count]]" % argv[0])
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exit()
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# arguments
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interval = 5
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count = -1
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if len(argv) > 1:
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try:
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interval = int(argv[1])
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if interval == 0:
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raise
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if len(argv) > 2:
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count = int(argv[2])
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except: # also catches -h, --help
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usage()
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# load BPF program
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b = BPF(src_file = "vfsreadlat.c")
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b.attach_kprobe(event="vfs_read", fn_name="do_entry")
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b.attach_kretprobe(event="vfs_read", fn_name="do_return")
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# header
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print("Tracing... Hit Ctrl-C to end.")
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# output
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loop = 0
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do_exit = 0
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while (1):
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if count > 0:
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loop += 1
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if loop > count:
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exit()
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try:
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sleep(interval)
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except KeyboardInterrupt:
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pass; do_exit = 1
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print()
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b["dist"].print_log2_hist("usecs")
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b["dist"].clear()
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if do_exit:
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exit()
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