Provided by: bpfcc-tools_0.18.0+ds-2_all bug


       ucalls,  javacalls,  perlcalls,  phpcalls,  pythoncalls,  rubycalls,  tclcalls - Summarize
       method calls from high-level languages and Linux syscalls.


       javacalls [-h] [-T TOP] [-L] [-S] [-v] [-m] pid [interval]
       perlcalls [-h] [-T TOP] [-L] [-S] [-v] [-m] pid [interval]
       phpcalls [-h] [-T TOP] [-L] [-S] [-v] [-m] pid [interval]
       pythoncalls [-h] [-T TOP] [-L] [-S] [-v] [-m] pid [interval]
       rubycalls [-h] [-T TOP] [-L] [-S] [-v] [-m] pid [interval]
       tclcalls [-h] [-T TOP] [-L] [-S] [-v] [-m] pid [interval]
       ucalls [-l {java,perl,php,python,ruby}] [-h] [-T TOP] [-L] [-S] [-v] [-m] pid [interval]


       This tool summarizes method calls from high-level  languages  such  as  Java,  Perl,  PHP,
       Python, Ruby, and Tcl. It can also trace Linux system calls. Whenever a method is invoked,
       ucalls records the call count and optionally the method's  execution  time  (latency)  and
       displays a summary.

       This uses in-kernel eBPF maps to store per process summaries for efficiency.

       This tool relies on USDT probes embedded in many high-level languages, such as Java, Perl,
       PHP, Python, Ruby, and Tcl. It requires a runtime instrumented with these probes, which in
       some  cases  requires  building  from source with a USDT-specific flag, such as "--enable-
       dtrace" or "--with-dtrace". For Java, method probes are not enabled by default, and can be
       turned  on  by running the Java process with the "-XX:+ExtendedDTraceProbes" flag. For PHP
       processes, the environment variable USE_ZEND_DTRACE must be set to 1.

       Since this uses BPF, only the root user can use this tool.


       CONFIG_BPF and bcc.


       -l {java,perl,php,python,ruby,tcl}
              The language to trace. If not provided, only  syscalls  are  traced  (when  the  -S
              option is used).

       -T TOP Print only the top methods by frequency or latency.

       -L     Collect method invocation latency (duration).

       -S     Collect Linux syscalls frequency and timing.

       -v     Print the resulting BPF program, for debugging purposes.

       -m     Print times in milliseconds (the default is microseconds).

       pid    The process id to trace.

              Print  summary  after  this  number  of seconds and then exit. By default, wait for
              Ctrl+C to terminate.


       Trace the top 10 Ruby method calls:
              # ucalls -T 10 -l ruby 1344

       Trace Python method calls and Linux syscalls including latency in milliseconds:
              # ucalls -l python -mL 2020

       Trace only syscalls and print a summary after 10 seconds:
              # ucalls -S 788 10


       Tracing individual method calls will produce a considerable  overhead  in  all  high-level
       languages.  For languages with just-in-time compilation, such as Java, the overhead can be
       more considerable than for interpreted languages.  On the other hand, syscall tracing will
       typically  be tolerable for most processes, unless they have a very unusual rate of system


       This is from bcc.


       Also look in the bcc distribution for a companion  _example.txt  file  containing  example
       usage, output, and commentary for this tool.




       Unstable - in development.


       Sasha Goldshtein


       ustat(8), argdist(8)