\input texinfo @c -*-texinfo-*-
@setfilename gprof.info
@c Copyright 1988, 1992, 1993, 1998, 1999, 2000, 2001, 2002, 2003,
-@c 2004, 2007
+@c 2004, 2007, 2008, 2009
@c Free Software Foundation, Inc.
@settitle GNU gprof
@setchapternewpage odd
This file documents the gprof profiler of the GNU system.
@c man begin COPYRIGHT
-Copyright @copyright{} 1988, 92, 97, 98, 99, 2000, 2001, 2003, 2007 Free Software Foundation, Inc.
+Copyright @copyright{} 1988, 1992, 1997, 1998, 1999, 2000, 2001, 2003,
+2007, 2008, 2009 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
+under the terms of the GNU Free Documentation License, Version 1.3
or any later version published by the Free Software Foundation;
with no Invariant Sections, with no Front-Cover Texts, and with no
Back-Cover Texts. A copy of the license is included in the
Eric S. Raymond made some minor corrections and additions in 2003.
@vskip 0pt plus 1filll
-Copyright @copyright{} 1988, 92, 97, 98, 99, 2000, 2003 Free Software Foundation, Inc.
+Copyright @copyright{} 1988, 1992, 1997, 1998, 1999, 2000, 2003, 2008,
+2009 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
+ under the terms of the GNU Free Documentation License, Version 1.3
or any later version published by the Free Software Foundation;
with no Invariant Sections, with no Front-Cover Texts, and with no
Back-Cover Texts. A copy of the license is included in the
version @value{VERSION}.
This document is distributed under the terms of the GNU Free
-Documentation License. A copy of the license is included in the
-section entitled ``GNU Free Documentation License''.
+Documentation License version 1.3. A copy of the license is included
+in the section entitled ``GNU Free Documentation License''.
@menu
* Introduction:: What profiling means, and why it is useful.
[ --static-call-graph ] [ --sum ] [ --table-length=@var{len} ]
[ --traditional ] [ --version ] [ --width=@var{n} ]
[ --ignore-non-functions ] [ --demangle[=@var{STYLE}] ]
- [ --no-demangle ] [ @var{image-file} ] [ @var{profile-file} @dots{} ]
+ [ --no-demangle ] [--external-symbol-table=name]
+ [ @var{image-file} ] [ @var{profile-file} @dots{} ]
@c man end
@end smallexample
ld -o myprog /lib/gcrt0.o myprog.o utils.o -lc_p
@end example
+If you are running the program on a system which supports shared
+libraries you may run into problems with the profiling support code in
+a shared library being called before that library has been fully
+initialised. This is usually detected by the program encountering a
+segmentation fault as soon as it is run. The solution is to link
+against a static version of the library containing the profiling
+support code, which for @code{gcc} users can be done via the
+@samp{-static} or @samp{-static-libgcc} command line option. For
+example:
+
+@example
+gcc -g -pg -static-libgcc myprog.c utils.c -o myprog
+@end example
+
If you compile only some of the modules of the program with @samp{-pg}, you
can still profile the program, but you won't get complete information about
the modules that were compiled without @samp{-pg}. The only information
The @samp{-n} option causes @code{gprof}, in its call graph analysis,
not to propagate times for symbols matching @var{symspec}.
+@item -S@var{filename}
+@itemx --external-symbol-table=@var{filename}
+The @samp{-S} option causes @code{gprof} to read an external symbol table
+file, such as @file{/proc/kallsyms}, rather than read the symbol table
+from the given object file (the default is @code{a.out}). This is useful
+for profiling kernel modules.
+
@item -z
@itemx --display-unused-functions
If you give the @samp{-z} option, @code{gprof} will mention all
ought to catch that function in the act only once, there is a pretty good
chance it will actually find that function zero times, or twice.
-By contrast, the number-of-calls and basic-block figures
-are derived by counting, not
-sampling. They are completely accurate and will not vary from run to run
-if your program is deterministic.
+By contrast, the number-of-calls and basic-block figures are derived
+by counting, not sampling. They are completely accurate and will not
+vary from run to run if your program is deterministic and single
+threaded. In multi-threaded applications, or single threaded
+applications that link with multi-threaded libraries, the counts are
+only deterministic if the counting function is thread-safe. (Note:
+beware that the mcount counting function in glibc is @emph{not}
+thread-safe). @xref{Implementation, ,Implementation of Profiling}.
The @dfn{sampling period} that is printed at the beginning of the flat
profile says how often samples are taken. The rule of thumb is that a
@node GNU Free Documentation License
@appendix GNU Free Documentation License
-@center Version 1.1, March 2000
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+@include fdl.texi
@bye