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| -rw-r--r-- | gprof/ChangeLog | 9 | ||||
| -rw-r--r-- | gprof/gprof.texi | 36 |
2 files changed, 37 insertions, 8 deletions
diff --git a/gprof/ChangeLog b/gprof/ChangeLog index 2e262ee..ead0226 100644 --- a/gprof/ChangeLog +++ b/gprof/ChangeLog @@ -1,3 +1,12 @@ +2003-10-29 Nick Clifton <nickc@redhat.com> + + * gprof.texi: Apply patch supplied by Eric S Raymond via RMS. + (Compiling): Mention that -pg must be passed to both the compiler + and the linker. + Mention that -a is now deprecated. + (How do I?): Add an entry describing how to get more information + about program hotspots. + 2003-10-11 Alan Modra <amodra@bigpond.net.au> * corefile.c (core_create_function_syms): Don't refer directly to diff --git a/gprof/gprof.texi b/gprof/gprof.texi index 9789ac7..3413d99 100644 --- a/gprof/gprof.texi +++ b/gprof/gprof.texi @@ -1,6 +1,6 @@ \input texinfo @c -*-texinfo-*- @setfilename gprof.info -@c Copyright 1988, 1992, 1993, 1998, 1999, 2000, 2001 +@c Copyright 1988, 1992, 1993, 1998, 1999, 2000, 2001, 2003 @c Free Software Foundation, Inc. @settitle GNU gprof @setchapternewpage odd @@ -19,7 +19,7 @@ END-INFO-DIR-ENTRY This file documents the gprof profiler of the GNU system. @c man begin COPYRIGHT -Copyright (C) 1988, 92, 97, 98, 99, 2000, 2001 Free Software Foundation, Inc. +Copyright (C) 1988, 92, 97, 98, 99, 2000, 2001, 2003 Free Software Foundation, Inc. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.1 @@ -53,9 +53,10 @@ This manual describes the @sc{gnu} profiler, @code{gprof}, and how you can use it to determine which parts of a program are taking most of the execution time. We assume that you know how to write, compile, and execute programs. @sc{gnu} @code{gprof} was written by Jay Fenlason. +Eric S. Raymond made some minor corrections and additions in 2003. @vskip 0pt plus 1filll -Copyright @copyright{} 1988, 92, 97, 98, 99, 2000 Free Software Foundation, Inc. +Copyright @copyright{} 1988, 92, 97, 98, 99, 2000, 2003 Free Software Foundation, Inc. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.1 @@ -278,6 +279,14 @@ The @samp{-pg} option also works with a command that both compiles and links: cc -o myprog myprog.c utils.c -g -pg @end example +Note: The @samp{-pg} option must be part of your compilation options +as well as your link options. If it is not, when you run @code{gprof} +you will get no profile report and an error message like this: + +@example +gprof: gmon.out file is missing call-graph data +@end example + If you run the linker @code{ld} directly instead of through a compiler such as @code{cc}, you may have to specify a profiling startup file @file{gcrt0.o} as the first input file instead of the usual startup @@ -307,10 +316,13 @@ instructing the compiler to insert debugging symbols into the program that match program addresses to source code lines. @xref{Line-by-line}. -In addition to the @samp{-pg} and @samp{-g} options, -you may also wish to specify the @samp{-a} option when compiling. -This will instrument -the program to perform basic-block counting. As the program runs, +In addition to the @samp{-pg} and @samp{-g} options, older versions of +GCC required you to specify the @samp{-a} option when compiling in +order to instrument it to perform basic-block counting. Newer +versions do not require this option and will not accept it; +basic-block counting is always enabled when @samp{-pg} is on. + +When basic-block counting is enabled, as the program runs it will count how many times it executed each branch of each @samp{if} statement, each iteration of each @samp{do} loop, etc. This will enable @code{gprof} to construct an annotated source code @@ -337,7 +349,7 @@ Your program will write the profile data into a file called @file{gmon.out} just before exiting. If there is already a file called @file{gmon.out}, its contents are overwritten. There is currently no way to tell the program to write the profile data under a different name, but you can rename -the file afterward if you are concerned that it may be overwritten. +the file afterwards if you are concerned that it may be overwritten. In order to write the @file{gmon.out} file properly, your program must exit normally: by returning from @code{main} or by calling @code{exit}. Calling @@ -1627,6 +1639,14 @@ nonce, the estimated figures are usually more useful than misleading. @chapter Answers to Common Questions @table @asis +@item How can I get more exact information about hot spots in my program? + +Looking at the per-line call counts only tells part of the story. +Because @code{gprof} can only report call times and counts by function, +the best way to get finer-grained information on where the program +is spending its time is to re-factor large functions into sequences +of calls to smaller ones. + @item How do I find which lines in my program were executed the most times? Compile your program with basic-block counting enabled, run it, then |