Script & help reminded for Dtrace & ruby

.Manage Dtrace

# Contains :
# * ruby_glob_analysis.d

Amazing quicksheet              : http://www.tablespace.net/quicksheet/dtrace-quickstart.html
Amasome one-liner               : https://wiki.freebsd.org/DTrace/One-Liners
Adding Probe dynamicly for ruby : https://github.com/kevinykchan/ruby-usdt
IP tracking                     : https://docs.oracle.com/cd/E36784_01/html/E36846/glhhr.html

# Main exemple :
ruby*:::method-entry
//execname == "ruby" && substr(copyinstr(arg2),0,38 ) == "/Users/sylvestre/codes/my_project/"/
// strstr(copyinstr(arg0), "/Users") != NULL -> Search for the first occurence ptr of '/user' into args0
{
  printf("-pid(%d)-------------------cwd(%s)------------------\n", pid, cwd);
  printf("execname(%s), probeprov(%s), probemod(%s), probefunc(%s), probename(%s)\n", execname, probeprov, probemod, probefunc, probename);
  printf("-> %s::%s (%s:%d)\n", copyinstr(arg0), copyinstr(arg1), copyinstr(arg2), arg3);
  printf("---------------------------------------\n");
  printf("%s\n", substr(copyinstr(arg2),0,38 ));
}

ruby_glob_analysis.d

// rm -f dtrace.log && sudo dtrace -q -s ruby_glob_analysis.d -p $( ps aux | grep 'rails s'|  grep -v grep | awk '{print $2}') > dtrace.log

#!/usr/sbin/dtrace -s
#pragma D option quiet

BEGIN
{
  start = timestamp;
}

ruby*:::method-entry
{
  self->time             = timestamp;
  @rbclasses[this->class = copyinstr(arg0)] = count();
  this->sep              = strjoin(this->class, "#");
  self->class_method     = strjoin(this->sep, copyinstr(arg1));
  @rbmethods_count[self->class_method] = count();
}

ruby*:::method-return
{
  this->took = (timestamp - self->time) / 1000000;
  @rbmethods_time[self->class_method] = sum(this->took);
}

ruby*:::object-create
{
  @created_objects[copyinstr(arg0), copyinstr(arg1)] = count();
}

syscall:::entry
/execname=="ruby"/
{
  @syscall_entries[probefunc, ustack(3)] = count();
}

END
{
  normalize(@rbclasses, (timestamp - start) / 1000000000);
  trunc(@rbclasses, 15);
  printf("\nClasses called (top 15 normalized) :\n");
  printf("---------------------------------------");
  printf("--------------------------------+------\n");
  printa("  %-68s | %@d\n", @rbclasses);

  normalize(@rbmethods_count, (timestamp - start) / 1000000000);
  trunc(@rbmethods_count, 15);
  printf("\nMethods called (top 15 normalized) :\n");
  printf("---------------------------------------");
  printf("--------------------------------+------\n");
  printa("  %-68s | %@d\n", @rbmethods_count);

  normalize(@created_objects, (timestamp - start) / 1000000000);
  trunc(@created_objects, 15);
  printf("\nObject created (top 15 normalized) :\n");
  printf("---------------------------------------");
  printf("--------------------------------+------\n");
  printa("  %-68s | %@d\n", @created_objects);
  //printa("  %-68s | %-68s | %@d\n", @created_objects); See also file associated

  normalize(@rbmethods_time, (timestamp - start) / 1000000000);
  trunc(@rbmethods_time, 15);
  printf("\nTime per method (top 15 normalized) :\n");
  printf("---------------------------------------");
  printf("--------------------------------+------\n");
  printa("  %-68s | %@d\n", @rbmethods_time);

  normalize(@syscall_entries, (timestamp - start) / 1000000000);
  trunc(@syscall_entries, 15);
  printf("\nSyscall method (top 15 normalized) :\n");
  printf("---------------------------------------");
  printf("--------------------------------+------\n");
  printa("  %-68s | %@d\n", @syscall_entries);
  //printa(@syscall_entries); See also the trace
}

// If concern relative with system call :
// 8thlight.com/blog/colin-jones/2015/12/01/ask-dtrace-why-are-my-tests-so-slow.html
// 1-Ensure : sudo dtrace -n 'syscall:::entry /execname=="ruby"/ { @[probefunc] = count(); } tick-1s { trunc(@,5); printa(@); trunc(@);}'
// 2-Find Why : sudo dtrace -n 'syscall::open:entry /execname=="ruby"/ { @[ustack()] = count(); } tick-1s { trunc(@,3); printa(@); trunc(@);}'
// 3-Find Where : sudo dtrace -n 'syscall::open:entry /execname=="ruby"/ { @[copyinstr(arg0)] = count(); } tick-1s { trunc(@,10); printa(@); trunc(@);}'

Here is a replacement : https://www.joyfulbikeshedding.com/blog/2019-01-31-full-system-dynamic-tracing-on-linux-using-ebpf-and-bpftrace.html

See also why there's memory bloat : https://www.joyfulbikeshedding.com/blog/2019-01-31-full-system-dynamic-tracing-on-linux-using-ebpf-and-bpftrace.html