||What is top?
Top provies the user with a regularly updated display showing
information about the system and its top cpu-using processes.
Think of it as a full-screen "ps" output that gets updated at
||Where do I get the latest version of top?
The official site for top is "ftp.unixtop.org" in the directory
"/pub/top". Top is also a SourceForge project, and the most recent
releases are available on any of the SourceForge mirrors. The SourceForge
project page is at http://sourceforge.net/projects/unixtop.|
||Is there a web page for top?
Yes. Point your browser at http://www.unixtop.org. It
includes all documentation, a nice interactive display which describes
the various components of the output of top, web-based retrieval of
the package, year 2000 information, and other neat stuff.|
||Is there a mailing list or on-line bulletin board for top?
There is a mailing list used for general announcements regarding top,
including new releases. This mailing list is available to sourceforge
members and can be accessed from the unixtop sourceforge project page.
Visit SourceForge and search for the project "unixtop", then click on
"mailing lists". There are also on-line forums available through
SourceForge where members can post questions and comments.|
||What about Year 2000 compliance?
Top did not experience any problems with the transition to the year
2000. A full statement concerning top and the year 2000 can be found
in the file "Y2K" included with the distribution.|
||Will there be another major release of top? Will there be a
top version 4?
I have some great ideas for the next major release of top, and I very
much want to make those ideas a reality. What I don't have much of these
days is free time. But I will keep poking at it and I hope to have top
version 4.0 ready by the fall of 2006.|
||Does top really support multi-processor systems?
On platforms that support multiple processors, top is able to detect and
correctly summarize the information about those processors. What top
does not do is break down the cpu states summary (the third line of
the display) by cpu. Instead it collects the cpu state information from
all processors and combines them in to a single line. Some vendors
include a modified version of top that presents this information for
each cpu. Top 3.7 may have this functionality but it is not present
in the standard top 3.6 release.|
||Is top under CVS control? Can I access the sources via
SourceForge CVS or Subversion?
I maintain top using subversion, not CVS. Although I utilize my own
private subversion repository, it is regularly mirrored in to the
SourceForge Subversion repository. You can access the SourceForge
repository here: https://svn.unixtop.org/unixtop/top-3.|
||We just upgraded our operating system to a new version and top
broke. What should we do?
Recompile it. Top is very sensitive to changes in internal kernel
data structures. It is not uncommon for a new version of the
operating system to include changes to kernel data structures.|
||I just finished compiling top and it works fine for root, but when
I try to run it as a regular user it either complains about files
it can't open or it doesn't display all the information it should.
Did I do something wrong?
Well, you're just not done. On many operating systems today, access
to many of the kernel memory devices and other system files is
restricted to either root or a particular group. The configure script
figures this out (usually) and makes sure that the "install" rule in
the Makefile will install top so that anyone can run it successfully.
However, you have to install it first. Do this with the command
||Top is (not) displaying idle processes and I don't (do) want
This default has only changed about a dozen times, and I finally got
tired of people whining about it. Go read the manual page for the
current version and pay special attention to the description of the
"TOP" environment variable.|
||We have so much memory in our machine that the memory status
display (the fourth line) ends up being longer than 80 characters. This
completely messes up top's output. Is there a patch?
Most modules have been changed to use new memory formatting functions
which will display large values in terms of megabytes instead of
kilobytes. This should fix all occurences of this problem. Also
note that newer versions of top can use columns beyond 79, and
understand window resizes. So you can always make your window wider.|
||I tried to compile top with gcc and it doesn't work. I get
compilation errors in the include files, or I get an executable that
dumps core, or top displays incorrect numbers in some of the displays.
Gnu CC likes very much to use its own include files. Not being a gcc
expert, I can't explain why it does this. But I can tell you that if
you upgrade your operating system (say from Solaris 2.6 to Solaris
2.7) after installing gcc, then the include files that gcc uses will
be incorrect, especially those found in the "sys" directory. Your
choices are: (1) rebuild and reinstall the "standard" include files
for gcc (look for scripts in the distribution called "fixincludes" and
"fixinc.svr4"), (2) compile machine.c with "CFLAGS=-I/usr/include"
then make the rest of the object files normally, or (3) use a
||The cpu state percentages are all wrong, indicating that my
machine is using 95% system time when it is clearly idle. What's wrong?
This can happen if you compiled with gcc using the wrong include
files. See the previous question.|
||This version of top does not show individual threads with
the "t" or "H" commands. Instead it says "command not available."
Previous versions of top attempted to support the display of individual
threads under FreeBSD through the use of the "t" command. However,
the FreeBSD kernel does not supply sufficient or correct information
on the individual threads within a process. So the data that was being
displayed was incorrect and misleading. Therefore, top version 3.8
disables the use of this command to prevent the display of incorrect
information. FreeBSD 8.0 will correctly report per-thread information
and top version 3.8 supports the use of the "t" command for version 8.0.|
||The "f" command (to display full command lines for the processes)
does not work and instead says "command not available". Why?
The current version of top is able to use sysctl to retrieve almost all of
the information it needs without having to open /dev/kmem. The one
piece of information not available via sysctl is the full command line
of each argument. If you run top as a regular user and it cannot open
/dev/kmem (in other words, it is not installed set-gid to the kmem group)
then it will disable the "f" command. Make sure the top binary is installed
with a group ownership of "kmem" and with the set-gid bit on if you want
the "f" command to work properly.|
||I tried to configure top on my Mac OSX system and I got
an error claiming "macosx not supported". What up?
Since I don't have full time root access to a Mac OSX system I cannot
provide effective support for the platform. MacOSX uses Mach, and it
is very difficult to extract accurate system and process information
from the system. It takes a lot of trial and error, along with root
access. I have included the most up-to-date version of the macosx module
in the distribution, but I do not claim that it works. If you want to
try to use it, you can configure with "./configure --with-module=macosx".|
||I tried compiling top under SunOS version 4.1.x and it
got compile time errors or run time errors. Is there a patch?
If you try compiling top in a "System V environment" under SunOS (that
is, /usr/5bin is before /usr/bin on your path) then the compilation
may fail. This is mostly due to the fact that top thinks its being
compiled on a System V machine when it really isn't. The only solution
is to put /usr/bin and /usr/ucb before /usr/5bin on your path and try
NOTE: the most common source of problems with top under Solaris is the
result of compiling it with the wrong front end. Make sure that /usr/ucb
is not on your path before attempting to compile top under Solaris.|
||Is there somewhere I can get a pre-compiled package?
Yes. Although I don't provide pre-compiled binaries, you can get a
Sun-style package from www.sunfreeware.com.|
||Under Solaris 2, when I type "make", the system says "language
optional software package not installed." What's going on?
You tried to compile with /usr/ucb/cc. Make sure /usr/ucb is not on
your path. Furthermore, you do not have a Sun compiler installed on
your system. You need a compiler to make top. Either Sun's C
compiler or the Gnu C compiler will work fine.|
||Under Solaris 2, when I run top as root it only shows root
processes, or it only shows processes with a PID less than 1000. It
refuses to show anything else. What do I do?
You probably compiled it with /usr/ucb/cc instead of the real C
compiler. /usr/ucb/cc is a cc front end that compiles programs in BSD
source-level compatability mode. You do not want that. Make sure
that /usr/ucb is not on your path and try compiling top again.|
||Under Solaris 2, I compiled top using what I am sure is the correct
compiler but when I try to run it it complains about missing dynamic
libraries. What is wrong?
Check to see if you have LD_LIBRARY_PATH defined in your shell. If
you do, make sure that /usr/ucblib is not on the path anywhere. Then
try compiling top again.|
||Under Solaris 2, when I try to run top it complains that it
can't open the library "libucb.so.1". So I changed the LIBS line in
m_sunos5.c to include -R/usr/ucblib to make sure that the dynamic
linker will look there when top runs. I figured this was just an
oversight. Was I right?
No, you were not right. As distributed, top requires no alterations
for successful compilation and operations under any release of Solaris
2. You probably compiled top with /usr/ucb/cc instead of the real C
compiler. See FAQ 22 for more details.|
||On my 64-bit system some processes show up with incorrect
information (such as zero memory).
If you are running a 64-bit system, then you need to make sure that
you are running the 64-bit top binary. Top's configure script
attempts to detect 64-bit systems, and will automatically generate
both 32-bit and 64-bit binaries on such systems. If you use or install
the 32-bit binary on a 64-bit system top will still run but will not
produce the correct results. This will also happen if you configure
your distribution on a 32-bit system then compile with that
configuration on a 64-bit system. You must configure and compile on
the same system. For Sparc systems the 32-bit binary will be created
in the subdirectory "sparcv7" and the 64-bit binary will be created
in the subdirectory "sparcv9". For Intel systems the directories will
be "i386" (32-bit) and "amd64" (64-bit). In all cases a copy of
/usr/lib/isaexec is made in the main directory and called "top". This
program will choose the correct binary to run from one of these
subdirectories. See isaexec(3c) for more details.|
||Can I install both 32-bit and 64-bit binaries on a
central file server and have machines which mount it automatically
use the correct one?
Yes. If you configure and compile on a 64-bit system, top's
configure script and makefile will automatically create both 32-bit
and 64-bit binaries. The "install" rule in the makefile will install
these binaries in subdirectories of /usr/local/bin appropriate to the
architecture (sparcv7/sparcv9 or i386/amd64) then create a copy of
/usr/lib/isaexec named "top" in /usr/local/bin to ensure that the
appropriate is run when a user types "top". If you make sure that
you configure and compile on a 64-bit system, then "make install"
will do the right thing.|
||This version of top show less available swap space than
previous versions. Why does it no longer match the output of the
swap summary produced with "swap -s"?
Starting with version 3.6 of top, the amount of swap space reported
by top has been changed to reflect only disk-based swap space. The
swap summary produced with "swap -s" also includes memory-based swap
space. This changed was made for several reasons. It makes the display
under Solaris more like those of other operating systems. The display
is more what users expect (except those used to previous versions of top).
Most importantly, "swap -s" gets its data via an undocumented system
interface. Now that top no longer displays that data it can use
publically documented and maintained system interfaces to retrieve
||When I run top on my SVR4-derived operating system, it
displays all the system information at the top but does not display
any process information (or only displays process information for my
own processes). Yet when I run it as root, everything works fine.
Your system probably uses the pseudo file system "/proc", which is by
default only accessible by root. Top needs to be installed setuid
root on such systems if it is going to function correctly for normal
||The memory display doesn't work right. Why?
This is a known bug with the svr42 module. The problem has been traced
down to a potential bug in the "mem" driver. The author of the svr42
module is working on a fix.|
||I'm still stuck. To whom do I report problems with top?
The most common problems are caused by top's sensitivity to internal
kernel data structures. So make sure that you are using the right
include files, and make sure that you test out top on the same machine
where you compiled it. Sun's BSD Source Compatability Mode is also a
common culprit. Make sure you aren't using either /usr/ucb/cc or any
of the libraries in /usr/ucblib. Finally, make sure you are using the
correct module. If there does not appear to be one appropriate for
your computer, then top probably will not work on your system.|
If after reading all of this file and checking everything you can you
are still stuck, then please use SourceForge to submit a support
request or a bug. Top is supported by the SourceForge project
named "unixtop". On SourceForge you will find defect tracking,
a mailing list, and on-line forums. You can also contact the
author through SourceForge.