strace of active record require and fopen calls.

gistfile1.txt

markw@markw-VirtualBox:~/Code/Ruby/testloadapp$ strace -eopen  ruby -r active_record -e ActiveRecord::Base 2>&1 | wc -l 
3462
markw@markw-VirtualBox:~/Code/Ruby/testloadapp$ strace -eopen ruby -r ./config/environment -e ActiveRecord::Base 2>&1 | wc -l
30873
markw@markw-VirtualBox:~/Code/Ruby/testloadapp$ 


https://gist.github.com/2478613


markw@markw-VirtualBox:~/Code/Ruby/testloadapp$ time ruby -r active_record -e ActiveRecord::Base

real	0m0.269s
user	0m0.224s
sys	0m0.044s
markw@markw-VirtualBox:~/Code/Ruby/testloadapp$ time ruby -r ./config/environment -e ActiveRecord::Base

real	0m1.231s
user	0m1.120s
sys	0m0.116s


time sudo dtrace -s syscallcount.d -c  "/Users/markw/.rbenv/versions/1.9.3-p125/bin/ruby -r ./config/environment -e ActiveRecord::Base"
dtrace: script 'syscallcount.d' matched 439 probes
dtrace: pid 52944 has exited

  __disable_threadsignal                                            1
  __semwait_signal                                                  1
  access                                                            1
  bsdthread_create                                                  1
  bsdthread_terminate                                               1
  exit                                                              1
  getrusage                                                         1
  mkdir                                                             1
  pipe                                                              1
  select                                                            1
  shm_open                                                          1
  thread_selfid                                                     1
  write                                                             1
  issetugid                                                         2
  __sysctl                                                          3
  fcntl                                                             6
  getrlimit                                                         6
  mprotect                                                          9
  read_nocancel                                                     9
  sigaction                                                        14
  pread                                                            27
  fstatfs64                                                        28
  chdir                                                            30
  munmap                                                           33
  __pthread_sigmask                                                34
  fcntl_nocancel                                                   45
  close_nocancel                                                   49
  getdirentries64                                                  58
  open_nocancel                                                    69
  mmap                                                            118
  lseek                                                           179
  stat64                                                          554
  getgid                                                          812
  getuid                                                          812
  getegid                                                         813
  geteuid                                                         814
  close                                                          1908
  ioctl                                                          1984
  read                                                           2165
  sigprocmask                                                    2342
  sigaltstack                                                    2343
  madvise                                                        3211
  fstat64                                                        3968
  lstat64                                                       11366
  open                                                          28352
sudo dtrace -s syscallcount.d -c   0.87s user 0.31s system 95% cpu 1.232 total

# cat syscalltime.d 
syscall:::entry
{
  k = probefunc;
}
tick-5000hz
/k != 0/
{
    @[k] = count();
}

time sudo dtrace -s syscallcount.d -c  "/Users/markw/.rbenv/versions/1.9.3-p125/bin/ruby -r active_record -e ActiveRecord::Base"       
dtrace: script 'syscallcount.d' matched 439 probes
dtrace: pid 52956 has exited

  __disable_threadsignal                                            1
  __semwait_signal                                                  1
  __sysctl                                                          1
  access                                                            1
  bsdthread_create                                                  1
  bsdthread_terminate                                               1
  exit                                                              1
  getrusage                                                         1
  pipe                                                              1
  select                                                            1
  shm_open                                                          1
  thread_selfid                                                     1
  write                                                             1
  fcntl_nocancel                                                    2
  fstatfs64                                                         2
  issetugid                                                         2
  getdirentries64                                                   5
  close_nocancel                                                    6
  fcntl                                                             6
  getrlimit                                                         6
  open_nocancel                                                     7
  read_nocancel                                                     9
  sigaction                                                        14
  munmap                                                           18
  pread                                                            18
  mmap                                                             75
  lseek                                                            87
  getgid                                                          345
  getuid                                                          345
  getegid                                                         346
  geteuid                                                         346
  __pthread_sigmask                                               509
  close                                                           816
  ioctl                                                           861
  read                                                            937
  sigprocmask                                                    1020
  sigaltstack                                                    1021
  fstat64                                                        1693
  madvise                                                        2739
  open                                                           2894
  stat64                                                         3761
  lstat64                                                        4801
sudo dtrace -s syscallcount.d -c   2.15s user 0.18s system 99% cpu 2.353 total


sudo dtrace -s syscalltime.d -c  "/Users/markw/.rbenv/versions/1.9.3-p125/bin/ruby -r active_record -e ActiveRecord::Base"
dtrace: script 'syscalltime.d' matched 440 probes
dtrace: pid 54941 has exited

  bsdthread_create                                                  1
  cltat64                                                           1
  exit                                                              1
  getattrlist                                                       1
  getppid                                                           1
  getrusage                                                         1
  psynch_cvbroad                                                    1
  psynch_mutexdrop                                                  1
  sigaltstvwait                                                     1
  thread_selfid                                                     1
  geteuid                                                           2
  getuid                                                            2
  lseek                                                             2
  open_nocancel                                                     2
  sem_post                                                          2
  psynch_mutexwait                                                  3
  read_nocancel                                                     3
  __mac_syscall                                                     4
  bsdthread_terminate                                               4
  sigaction                                                         4
  getegid                                                           5
  write                                                             5
  proc_info                                                         6
  sigprocmask                                                       6
  getrlimit                                                         7
  getdirentries64                                                   9
  getgid                                                           10
  fstat64                                                          27
  close_nocancel                                                   29
  psynch_cvsignal                                                  30
  gettimeofday                                                     31
  sigsuspend                                                       35
  poll                                                             46
  mmap                                                             48
  __sysctl                                                         59
  pread                                                            60
  ioctl                                                            61
  munmap                                                           63
  workq_kernreturn                                                 86
  sigaltstack                                                     101
  __pthread_sigmask                                               102
  __semwait_signal                                                104
  open                                                            155
  stat64                                                          401
  select                                                          756
  close                                                           915
  kevent                                                         1135
  madvise                                                        1818
  read                                                           2257
  psynch_cvwait                                                  3957
  lstat64                                                        4208


sudo dtrace -s syscalltime.d -c  "/Users/markw/.rbenv/versions/1.9.2-p290/bin/ruby -r active_record -e ActiveRecord::Base"
dtrace: script 'syscalltime.d' matched 440 probes
dtrace: pid 54980 has exited

  fstat64                                                           1
  getdirentries64                                                   1
  getrlimit                                                         1
  gpen                                                              1
  opea                                                              1
  open_nocancel                                                     1
  pread                                                             1
  psynch_cvsignal                                                   1
  read_nocancel                                                     1
  sigprostack                                                       1
  __sysctl                                                          2
  getgid                                                            2
  proc_info                                                         2
  close_nocancel                                                    3
  sigprocmask                                                       3
  issetugid                                                         4
  mmap                                                              4
  sigaltstack                                                       4
  madvise                                                           5
  __semwait_signal                                                  8
  getegid                                                           8
  __pthread_sigmask                                                11
  ioctl                                                            12
  munmap                                                           15
  sigaction                                                        19
  stat64                                                           22
  workq_kernreturn                                                 27
  select                                                           38
  kevent                                                           75
  open                                                             85
  psynch_cvwait                                                   119
  close                                                           132
  read                                                            380
  lstat64                                                        1727

For the record, @wolfeidau pinned this down to the RubyGems version.

# RubyGems 1.8.11, Ruby 1.9.3p0: 2.88 seconds

paul@paulbookpro ~/tmp ⸩ time ruby -r active_record -e ActiveRecord::Base
ruby -r active_record -e ActiveRecord::Base  2.74s user 0.13s system 99% cpu 2.882 total

paul@paulbookpro ~/tmp ⸩ time ruby -r ./config/environment -e ActiveRecord::Base
ruby -r ./config/environment -e ActiveRecord::Base  1.78s user 0.39s system 89% cpu 2.410 total

# RubyGems 1.8.23, Ruby 1.9.3p0: 0.82 seconds

paul@paulbookpro ~/tmp ⸩ time ruby -r active_record -e ActiveRecord::Base
ruby -r active_record -e ActiveRecord::Base  0.69s user 0.13s system 99% cpu 0.824 total

paul@paulbookpro ~/tmp ⸩ time ruby -r ./config/environment -e ActiveRecord::Base
ruby -r ./config/environment -e ActiveRecord::Base  2.22s user 0.42s system 99% cpu 2.644 total