FreeBSD src
appear to be never called: (1) If a function is never called according to its call count but it must have been called because its child time is nonzero, then print it in the flat profile. Previously, if its call count was zero then we only printed it in the flat profile if its self time was nonzero. (2) If a function has a zero call count but has a nonzero self or child time, then print its total self time in the self time per call column as a percentage of the total (self + child) time. It is not possible to print the times per call in this case because the call count is zero. Previously, this was handled by leaving both per-call columns blank. The self time is printed in another column but there was no way to recover the total time. (1) partially fixes the case of the "never called" function main() and prepares for (2) to apply to main() and other functions. Profiling of main() was lost in the conversion from a.out to ELF, so main()'s call count has always been zero for many years; then in the common case where main() is a tiny function, it gets no profiling ticks, so main() was completely lost in the flat profile. (2) improves mainly cases like kernel threads. Most kernel threads appear to be never called because they are always started before userland can run to turn on profiling. As for main(), the fact that they are called is not very interesting and their callers are uninteresting, but their relative self time is interesting since they are long-running. Almost always printing percentages in the per-call columns would be more useful than almost always printing 0.0ms. 0.1ms is now a long time, so only very large functions take that long per call. The accuracy per call can approach 1-10 nsec provided programs are run for about 100000 times as long as is necessary to get this accuracy with high resolution kernel profiling. |
||
---|---|---|
bin | ||
contrib | ||
crypto | ||
etc | ||
games | ||
gnu | ||
include | ||
kerberos5 | ||
lib | ||
libexec | ||
release | ||
rescue | ||
sbin | ||
secure | ||
share | ||
sys | ||
tools | ||
usr.bin | ||
usr.sbin | ||
COPYRIGHT | ||
LOCKS | ||
MAINTAINERS | ||
Makefile | ||
Makefile.inc1 | ||
ObsoleteFiles.inc | ||
README | ||
UPDATING |
This is the top level of the FreeBSD source directory. This file was last revised on: $FreeBSD$ For copyright information, please see the file COPYRIGHT in this directory (additional copyright information also exists for some sources in this tree - please see the specific source directories for more information). The Makefile in this directory supports a number of targets for building components (or all) of the FreeBSD source tree, the most commonly used one being ``world'', which rebuilds and installs everything in the FreeBSD system from the source tree except the kernel, the kernel-modules and the contents of /etc. The ``buildkernel'' and ``installkernel'' targets build and install the kernel and the modules (see below). Please see the top of the Makefile in this directory for more information on the standard build targets and compile-time flags. Building a kernel is a somewhat more involved process, documentation for which can be found at: http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/kernelconfig.html And in the config(8) man page. Note: If you want to build and install the kernel with the ``buildkernel'' and ``installkernel'' targets, you might need to build world before. More information is available in the handbook. The sample kernel configuration files reside in the sys/<arch>/conf sub-directory (assuming that you've installed the kernel sources), the file named GENERIC being the one used to build your initial installation kernel. The file NOTES contains entries and documentation for all possible devices, not just those commonly used. It is the successor of the ancient LINT file, but in contrast to LINT, it is not buildable as a kernel but a pure reference and documentation file. Source Roadmap: --------------- bin System/user commands. contrib Packages contributed by 3rd parties. crypto Cryptography stuff (see crypto/README). etc Template files for /etc. games Amusements. gnu Various commands and libraries under the GNU Public License. Please see gnu/COPYING* for more information. include System include files. kerberos5 Kerberos5 (Heimdal) package. lib System libraries. libexec System daemons. release Release building Makefile & associated tools. sbin System commands. secure Cryptographic libraries and commands. share Shared resources. sys Kernel sources. tools Utilities for regression testing and miscellaneous tasks. usr.bin User commands. usr.sbin System administration commands. For information on synchronizing your source tree with one or more of the FreeBSD Project's development branches, please see: http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/synching.html