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.TH eprof 3 "tools 2.6.1" "Ericsson AB" "ERLANG MODULE DEFINITION"
.SH MODULE
eprof \- A Time Profiling Tool for Erlang
.SH DESCRIPTION
.LP
The module \fIeprof\fR provides a set of functions for time profiling of Erlang programs to find out how the execution time is used\&. The profiling is done using the Erlang trace BIFs\&. Tracing of local function calls for a specfied set of processes is enabled when profiling is begun, and disabled when profiling is stopped\&.
.LP
When using Eprof, expect a significant slowdown in program execution, in most cases at least 100 percent\&.
.SH EXPORTS
.LP
.B
start() -> {ok,Pid} | {error,Reason}
.br
.RS
.TP
Types
Pid = pid()
.br
Reason = {already_started, Pid}
.br
.RE
.RS
.LP
Starts the Eprof server which owns the Eprof internal database\&.
.RE
.LP
.B
start_profiling(Rootset) -> profiling | error
.br
.B
profile(Rootset) -> profiling | error
.br
.RS
.TP
Types
Rootset = [atom() | pid()]
.br
.RE
.RS
.LP
Starts profiling for the processes in \fIRootset\fR (and any new processes spawned from them)\&. Information about activity in any profiled process is stored in the Eprof database\&.
.LP
\fIRootset\fR is a list of pids and registered names\&.
.LP
The function returns \fIprofiling\fR if tracing could be enabled for all processes in \fIRootset\fR, or \fIerror\fR otherwise\&.
.RE
.LP
.B
stop_profiling() -> profiling_stopped | profiling_already_stopped
.br
.RS
.LP
Stops profiling started with \fIstart_profiling/1\fR or \fIprofile/1\fR\&.
.RE
.LP
.B
profile(Rootset,Fun) -> {ok,Value} | {error,Reason} | error
.br
.B
profile(Rootset,Module,Function,Args) -> {ok,Value} | {error,Reason} | error
.br
.RS
.TP
Types
Rootset = [atom() | pid()]
.br
Fun = fun() -> term()
.br
Module = Function = atom()
.br
Args = [term()]
.br
Value = Reason = term()
.br
.RE
.RS
.LP
This function first spawns a process \fIP\fR which evaluates \fIFun()\fR or \fIapply(Module, Function, Args)\fR\&. Then, it starts profiling for \fIP\fR and the processes in \fIRootset\fR (and any new processes spawned from them)\&. Information about activity in any profiled process is stored in the Eprof database\&.
.LP
\fIRootset\fR is a list of pids and registered names\&.
.LP
If tracing could be enabled for \fIP\fR and all processes in \fIRootset\fR, the function returns \fI{ok, Value}\fR when \fIFun()\fR/\fIapply\fR returns with the value \fIValue\fR, or \fI{error, Reason}\fR if \fIFun()\fR/\fIapply\fR fails with exit reason \fIReason\fR\&. Otherwise it returns \fIerror\fR immediately\&.
.LP
The programmer must ensure that the function given as argument is truly synchronous and that no work continues after the function has returned a value\&.
.RE
.LP
.B
analyse()
.br
.RS
.LP
Call this function when profiling has been stopped to display the results per process, that is:
.RS 2
.TP 2
*
how much time has been used by each process, and
.TP 2
*
in which function calls this time has been spent\&.
.RE
.LP
Time is shown as percentage of total time, not as absolute time\&.
.RE
.LP
.B
total_analyse()
.br
.RS
.LP
Call this function when profiling has been stopped to display the results per function call, that is in which function calls the time has been spent\&.
.LP
Time is shown as percentage of total time, not as absolute time\&.
.RE
.LP
.B
log(File) -> ok
.br
.RS
.TP
Types
File = atom() | string()
.br
.RE
.RS
.LP
This function ensures that the results displayed by \fIanalyse/0\fR and \fItotal_analyse/0\fR are printed both to the file \fIFile\fR and the screen\&.
.RE
.LP
.B
stop() -> stopped
.br
.RS
.LP
Stops the Eprof server\&.
.RE
|
