100 lines
4.2 KiB
Plaintext
100 lines
4.2 KiB
Plaintext
Why does "ps -aux" complain about a bogus '-'?
|
|
|
|
According to the POSIX and UNIX standards, the above command asks to display
|
|
all processes with a TTY (generally the commands users are running) plus all
|
|
processes owned by a user named "x". If that user doesn't exist, then ps will
|
|
assume you really meant "ps aux". The warning is given to gently break you of a
|
|
habit that will cause you trouble if a user named "x" were created.
|
|
|
|
|
|
Why don't I see SMP (per-CPU) stats in top?
|
|
|
|
You didn't enable it. Press '?' for built-in help or read the man page. Per-CPU
|
|
stats are disabled by default because they take up too much space. Some Linux
|
|
systems have hundreds of CPUs.
|
|
|
|
|
|
Why do long usernames get printed as numbers?
|
|
|
|
The UNIX and POSIX standards require that user names and group names be printed
|
|
as decimal integers when there is not enough room in the column. Truncating the
|
|
names, besides being a violation of the standard, would lead to confusion
|
|
between names like MichelleRichards and MichelleRichardson. The UNIX and POSIX
|
|
way to change column width is to rename the column:
|
|
|
|
ps -o pid,user=CumbersomeUserNames -o comm
|
|
|
|
The easy way is to directly specify the desired width:
|
|
|
|
ps -o pid,user:19,comm
|
|
|
|
|
|
Why is %CPU underreported for multi-threaded (Java, etc.) apps?
|
|
|
|
You need to upgrade to the 2.6.10 kernel at least. Older kernels do not provide
|
|
a reasonable way to get this information.
|
|
|
|
|
|
Why do ps and top show threads individually?
|
|
|
|
The 2.4.xx kernel does not provide proper support for grouping threads by
|
|
process. Hacks exist to group them anyway, but such hacks will falsely group
|
|
similar tasks and will fail to group tasks due to race conditions. The hacks
|
|
are also slow. As none of this is acceptable in a critical system tool, task
|
|
grouping is not currently available for the 2.4.xx kernel. The 2.6.xx kernel
|
|
allows for proper thread grouping and reporting. To take advantage of this,
|
|
your programs must use a threading library that features the CLONE_THREAD flag.
|
|
The NPTL pthreads provided by recent glibc releases use CLONE_THREAD.
|
|
|
|
|
|
What systems are supported?
|
|
|
|
Linux 2.4.xx and 2.6.xx are commonly tested and expected to work well. SMP is
|
|
well supported. Multi-node cluster views require a multi-node /proc filesystem;
|
|
without that you will see a single-node view.
|
|
|
|
|
|
Where to I send bug reports?
|
|
|
|
You may use the Debian bug tracking system or send your report to
|
|
procps@freelists.org (no subscription required) instead.
|
|
|
|
|
|
Why are there so many procps projects?
|
|
|
|
The original maintainer seems to have had little time for procps. Whatever his
|
|
reasons, the project didn't get maintained. Starting in 1997, Albert Cahalan
|
|
wrote a new ps program for the package. For the next few years, Albert quietly
|
|
helped the Debian package maintainer fix bugs. In 2001, Rik van Riel decided to
|
|
do something about what appeared to be the lack of a maintainer. He picked up
|
|
the buggy old code in Red Hat's CVS and started adding patches. Meanwhile,
|
|
other people have patched procps in a great many ways.
|
|
|
|
In 2002, Albert moved procps to http://procps.sourceforge.net. This was done to
|
|
ensure that years of testing and bug fixes would not be lost. The major version
|
|
number was changed to 3, partly to avoid confusing users and partly because the
|
|
top program had been redone.
|
|
|
|
After development essentially stopped on sourceforge.net, in 2011 the project
|
|
found a new home at http://gitorious.org/procps. This represents the Debian,
|
|
Fedora and openSUSE fork of procps. To avoid confusion and potential name
|
|
clashes the package is now known as procps-ng (next generation), the version
|
|
number was raised to 3.3.0 and the library soname changed to libproc-ng-3.3.0.
|
|
|
|
|
|
What is being done to procps-ng at its new home?
|
|
|
|
All programs are in the process of being modernized, both in terms of coding
|
|
style and supporting documentation. Autotools have been integrated and the
|
|
library API has been expanded with many new fields supported such as control
|
|
groups, supplementary groups, etc. The top program has been rewritten offering
|
|
many new capabilities while providing performance improvements up to 300%.
|
|
|
|
|
|
Why does ps get signal 17?
|
|
|
|
No ps release has ever had this problem. Most likely your system has been
|
|
broken into. You might want to install a more recent version of the OS. If
|
|
you'd rather take your chances, simply upgrade procps.
|
|
|