BIND 10 #1565: document how to profile - gprof

[BIND 10 Development]

#1565: document how to profile - gprof
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                   Reporter:  jelte  |                 Owner:  haikuo
                       Type:  task   |                Status:  accepted
                   Priority:  major  |             Milestone:
                  Component:         |  Sprint-20120207
  Unclassified                       |            Resolution:
                   Keywords:         |             Sensitive:  0
            Defect Severity:  N/A    |           Sub-Project:  DNS
Feature Depending on Ticket:         |  Estimated Difficulty:  0
        Add Hours to Ticket:  0      |           Total Hours:  0
                  Internal?:  0      |
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Comment (by haikuo):

 when we use "pg" option to build bind10 software, all the ELF executable
 files(eg. b10-auth and b10-resolver in PATH/libexec/bind10-devel/) would
 produce the same default profiling file which named "gmon.out" at the same
 working directory.
 If want to produce different files, we should assign different values to
 the "GMON_OUT_PREFIX" environmental variable when spawn different sub-
 processes. Take from example, b10-auth ELF executable file will produce
 b10-auth.PID file if we assign "b10-auth" to "GMON_OUT_PREFIX",and
 b10-resolver ELF executable file will produce b10-resolver.PID file when
 we assign "b10-resolver" to  "GMON_OUT_PREFIX".


 I have a suggestion to handle the name conflict. we could modify the
 bind10 scripts in PATH/sbin, add "spawn_env['GMON_OUT_PREFIX'] =
 self.args[0]" to _spawn function, like that:

 [zhanghk at iscloud01 tmp]$ diff bind10 bind10-new
 144a145
 >         spawn_env['GMON_OUT_PREFIX'] = self.args[0]

 then bind10 will produce different profiling files, and we can use gprof
 to collect data for the differenct ELF executable files .

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Ticket URL: <http://bind10.isc.org/ticket/1565#comment:3>
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