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@@ -0,0 +1,97 @@ +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 2.6.xx and 3.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 so-name changed to libprocps.so + +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. |