From: jimmy jam Date: Tue, 4 Oct 2011 17:16:30 +0000 (-0500) Subject: add the customary redhat FAQ X-Git-Tag: v3.3.0~7^2~18 X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=ee2e674182a008f66d82ab9d25eb117057458c60;p=procps-ng add the customary redhat FAQ --- diff --git a/FAQ b/FAQ new file mode 100644 index 00000000..ae9df265 --- /dev/null +++ b/FAQ @@ -0,0 +1,82 @@ +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-feedback@lists.sf.net (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 this site. 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 has been redone. + + +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. +