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      1 Demonstrations of ucalls.
      2 
      3 
      4 ucalls summarizes method calls in various high-level languages, including Java,
      5 Perl, PHP, Python, Ruby, Tcl, and Linux system calls. It displays statistics on
      6 the most frequently called methods, as well as the latency (duration) of these
      7 methods.
      8 
      9 Through the syscalls support, ucalls can provide basic information on a 
     10 process' interaction with the system including syscall counts and latencies. 
     11 This can then be used for further exploration with other BCC tools like trace,
     12 argdist, biotop, fileslower, and others.
     13 
     14 For example, to trace method call latency in a Java application:
     15 
     16 # ucalls -L $(pidof java)
     17 Tracing calls in process 26877 (language: java)... Ctrl-C to quit.
     18 
     19 METHOD                                              # CALLS TIME (us)
     20 java/io/BufferedInputStream.getBufIfOpen                  1 7.00
     21 slowy/App.isSimplePrime                                8970 8858.35
     22 slowy/App.isDivisible                               3228196 3076985.12
     23 slowy/App.isPrime                                      8969 4841017.64
     24 ^C
     25 
     26 
     27 To trace only syscalls in a particular process and print the top 10 most 
     28 frequently-invoked ones:
     29 
     30 # ucalls -ST 10 3018
     31 Attached 375 kernel probes for syscall tracing.
     32 Tracing calls in process 3018 (language: none)... Ctrl-C to quit.
     33 
     34 METHOD                                              # CALLS
     35 sys_rt_sigaction                                          4
     36 SyS_rt_sigprocmask                                        4
     37 sys_mprotect                                              5
     38 sys_read                                                 22
     39 SyS_write                                                39
     40 SyS_epoll_wait                                           42
     41 sys_futex                                               177
     42 SyS_mmap                                                180
     43 sys_mmap_pgoff                                          181
     44 sys_munmap                                              817
     45 ^C
     46 Detaching kernel probes, please wait...
     47 
     48 
     49 To print only the top 5 methods and report times in milliseconds (the default
     50 is microseconds):
     51 
     52 # ucalls -mT 5 $(pidof python)
     53 Tracing calls in process 26914 (language: python)... Ctrl-C to quit.
     54 
     55 METHOD                                              # CALLS
     56 <stdin>.<module>                                          1
     57 <stdin>.fibo                                       14190928
     58 ^C
     59 
     60 
     61 USAGE message:
     62 
     63 # ./ucalls.py -h
     64 usage: ucalls.py [-h] [-l {java,perl,php,python,ruby,tcl,none}] [-T TOP] [-L] [-S] [-v]
     65                  [-m]
     66                  pid [interval]
     67 
     68 Summarize method calls in high-level languages.
     69 
     70 positional arguments:
     71   pid                   process id to attach to
     72   interval              print every specified number of seconds
     73 
     74 optional arguments:
     75   -h, --help            show this help message and exit
     76   -l {java,perl,php,python,ruby,tcl,none}, --language {java,perl,php,python,ruby,tcl,none}
     77                         language to trace (if none, trace syscalls only)
     78   -T TOP, --top TOP     number of most frequent/slow calls to print
     79   -L, --latency         record method latency from enter to exit (except
     80                         recursive calls)
     81   -S, --syscalls        record syscall latency (adds overhead)
     82   -v, --verbose         verbose mode: print the BPF program (for debugging
     83                         purposes)
     84   -m, --milliseconds    report times in milliseconds (default is microseconds)
     85 
     86 examples:
     87     ./ucalls -l java 185        # trace Java calls and print statistics on ^C
     88     ./ucalls -l python 2020 1   # trace Python calls and print every second
     89     ./ucalls -l java 185 -S     # trace Java calls and syscalls
     90     ./ucalls 6712 -S            # trace only syscall counts
     91     ./ucalls -l ruby 1344 -T 10 # trace top 10 Ruby method calls
     92     ./ucalls -l ruby 1344 -L    # trace Ruby calls including latency
     93     ./ucalls -l php 443 -LS     # trace PHP calls and syscalls with latency
     94     ./ucalls -l python 2020 -mL # trace Python calls including latency in ms
     95