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