FIX: atoi, take #2

Before:

[penberg@localhost libtrading]$ perf stat taskset -c 2 tools/fix/fix_client -m 2 -h localhost -p 7070 -n 100000
Client Logon OK
Messages sent: 100000
Round-trip time: min/avg/max = 15.0/15.5/485.0 μs
Client Logout OK

 Performance counter stats for 'taskset -c 2 tools/fix/fix_client -m 2 -h localhost -p 7070 -n 100000':

       1623.392443      task-clock (msec)         #    0.998 CPUs utilized
                12      context-switches          #    0.007 K/sec
                 4      cpu-migrations            #    0.002 K/sec
               605      page-faults               #    0.373 K/sec
     5,092,134,383      cycles                    #    3.137 GHz                     [83.33%]
     2,400,110,182      stalled-cycles-frontend   #   47.13% frontend cycles idle    [83.33%]
     1,514,628,090      stalled-cycles-backend    #   29.74% backend  cycles idle    [66.69%]
     6,314,026,809      instructions              #    1.24  insns per cycle
                                                  #    0.38  stalled cycles per insn [83.39%]
     1,148,801,918      branches                  #  707.655 M/sec                   [83.39%]
         6,626,195      branch-misses             #    0.58% of all branches         [83.27%]

       1.626275156 seconds time elapsed

After:

[penberg@localhost libtrading]$ perf stat taskset -c 2 tools/fix/fix_client -m 2 -h localhost -p 7070 -n 100000
Client Logon OK
Messages sent: 100000
Round-trip time: min/avg/max = 14.0/15.4/434.0 μs
Client Logout OK

 Performance counter stats for 'taskset -c 2 tools/fix/fix_client -m 2 -h localhost -p 7070 -n 100000':

       1585.542173      task-clock (msec)         #    0.998 CPUs utilized
                11      context-switches          #    0.007 K/sec
                 3      cpu-migrations            #    0.002 K/sec
               607      page-faults               #    0.383 K/sec
     4,924,298,362      cycles                    #    3.106 GHz                     [83.31%]
     2,272,636,404      stalled-cycles-frontend   #   46.15% frontend cycles idle    [83.33%]
     1,413,842,968      stalled-cycles-backend    #   28.71% backend  cycles idle    [66.75%]
     6,211,535,097      instructions              #    1.26  insns per cycle
                                                  #    0.37  stalled cycles per insn [83.38%]
     1,124,905,511      branches                  #  709.477 M/sec                   [83.37%]
         5,976,068      branch-misses             #    0.53% of all branches         [83.25%]

       1.588288580 seconds time elapsed

Signed-off-by: Pekka Enberg <penberg@iki.fi>
Latest latency numbers

Signed-off-by: Pekka Enberg <penberg@iki.fi>