Often pidof is used in shell scripts in this form:
if pidof daemon >/dev/null; then
...
fi
The redirection to /dev/null is needed because otherwise the script
would output the found PIDs.
Let's add a -q option which, similary to grep, just sets the exit code.
Also exit on first match, as there is no reason to proceed further when
at least a process is matched.
Tested with:
$ ./pidof bash
17701 14019 5276 2967
$ echo $?
0
$ ./pidof bashx
$ echo $?
1
$ ./pidof -q bash
$ echo $?
0
$ ./pidof -q bashx
$ echo $?
1
See https://en.wikipedia.org/wiki/ANSI_escape_code#8-bit
Support standard and high intensity colors. The default
ncurses colors ARE the high intensity colors - represented
via an 8 bit ansi escape sequence here.
See https://en.wikipedia.org/wiki/ANSI_escape_code#8-bit
Support standard and high intensity colors. The default
ncurses colors ARE the high intensity colors - represented
via an 8 bit ansi escape sequence here.
We read /proc/stat using a statically sized buffer. This was increased
to 64kB in 2005 via commit 777fcd3cf1 "/proc/stat for 1024 CPUs".
Unfortunately in 2020, 1024 CPUs is not enough for anyone. I have a
large machine where /proc/stat is 74kB, and vmstat gives incorrect
output.
Double the buffer to 128kB in the confidence that 2048 CPUs is actually
enough for anyone.
Signed-off-by: Anton Blanchard <anton@ozlabs.org>
New command, pwait! Waits for another process to finish just like
pgrep finds or pkill kills another process.
References:
procps-ng/procps!97
Signed-off-by: Craig Small <csmall@dropbear.xyz>
With glibc, each time the strftime() function is used (twice per process
in a typical ps -fe run), a stat("/etc/localtime") system call is used
to determine the timezone. Not only does this add extra system call
overhead, but when multiple ps processes are trying to access this
file (or multiple glibc programs using strftime) in parallel, this can
trigger significant lock contention within the OS kernel.
Since ps is not intended to run for long periods of time as a
daemon (during which the system timezone could be altered and PS might
reasonably be expected to adapt its output), there is no benefit to
repeatedly doing this stat(). To stop this behavior, explicitly set the
TZ variable to its default value (:/etc/localtime) whenever it is unset.
glibc will then cache the stat() result.
While sysctl did change the order of /run and /etc to match
systemd in the referenced commit, the Debian bug report that
brought it to light was not documented.
References:
commit 24a1574f0ahttps://bugs.debian.org/950788
If a hash results report was output (via ATEOJ_RPTHSH)
a portion is devoted to occupied table entries ordered
by depth. There is a possibility that some depths will
not be found among existing occupied table entries and
to avoid any confusion probably should not be printed.
[ to illustrate the potential for confusion prior to ]
[ this patch, force a very small table size (like 8) ]
[ and then arrange to trigger the end-of-job report. ]
So this patch ensures only 'in use' entries are shown.
[ admittedly, all of the remaining logic in the loop ]
[ could/should be subordinate to this new 'if' test, ]
[ but we will keep the change to a minimum. besides, ]
[ there's no harm subtracting/adding a zero numdepth ]
[ especially since the chance of a zero is very low. ]
Signed-off-by: Jim Warner <james.warner@comcast.net>
free, slabtop and uptime would happily take extra command line
arguments and doing nothing about them. The programs now check
optind after option processing and will give you usage screen
if there is anything extra.
References:
procps-ng/procps#181
For long lines from a process, watch would wrap them around to the
next. While this default option has it uses, sometimes you want to
just cut those long lines down.
watch has a -w flag which will truncate the lines to the number
of columns. A few simple lines to do this new trick.
I think I caught all the ANSI state correctly but there might be
a chance it bleeds to the next row.
References:
procps-ng/procps#182
This patch just raises the size of the hash table used
to calculate elapsed task stuff. The net result should
be less need for 'chaining' under pid hash collisions.
[ the hash scheme is intentionally kept as primitive ]
[ and, therefore, as fast as possible. it employs an ]
[ 'and' approach versus a 'mod' operation since both ]
[ yield similar distribution but the former approach ]
[ was 4 fewer cpu instructions in terms of overhead. ]
[ additionally, for hash collisions, 'chaining' uses ]
[ an array index rather than the usual pointer since ]
[ the HST_t guys may move when they are reallocated. ]
Signed-off-by: Jim Warner <james.warner@comcast.net>
The referenced commit the comm length was increased from 16 to 64
characters to handle the larger command names for things like kernel
threads.
However most user processes are limited to 15 characters which means
if you try something like ps -C myprogramisbiggerthansixteen this would
fail to match because /proc/<PID>/comm would only be myprogramisbigg
ps now checks the comm length and if it is 15 and if the given match
is 15 or more, it will only match the first 15 characters.
This is also how killall has worked for about a year.
Thanks to Jean Delvare <jdelvare@suse.de> for the note.
References:
commit 14005a371e
commit psmisc/psmisc@1188315cd0
Signed-off-by: Craig Small <csmall@dropbear.xyz>
This patch is an outgrowth of that commit shown below.
Many additional potential segmentation faults might be
encountered if interactive commands are opened up to a
user when a '-p' switch has a single non-existent pid.
[ always the 'k', 'L', 'r', 'Y' keys & maybe 'v' too ]
So, this patch will restrict such a loser (oops, user)
to a reduced subset of normal commands until he/she/it
quits then restarts top with something to be displayed
or issues the '=' command overriding that '-p' switch.
Reference(s):
commit f57a0301e3
Signed-off-by: Jim Warner <james.warner@comcast.net>
This patch fixes a nearly decade old bug discovered by
Frederik Deweerdt. His merge request shown below would
be an adequate solution except for iterative overhead.
This alternate patch will represent substantially less
overhead for an admittedly extremely rare possibility.
Reference(s):
https://gitlab.com/procps-ng/procps/-/merge_requests/114
And-thanks-to: Frederik Deweerdt <fdeweerdt@fastly.com>
Signed-off-by: Jim Warner <james.warner@comcast.net>
What had been stated as the contents of the cpu graphs
was never really inclusive enough. Those recent newlib
tweaks highlighted the need for these man doc changes.
Signed-off-by: Jim Warner <james.warner@comcast.net>
[ this is what happens when i've run out of bugs and ]
[ issues and am now left with way too much free time ]
Signed-off-by: Jim Warner <james.warner@comcast.net>
All of these changes are self-explanatory, so I'll not
provide any more comments thus avoiding further shame.
[ everything's perfectly justified and right margins ]
[ are filled entirely, but of course it must be luck ]
Signed-off-by: Jim Warner <james.warner@comcast.net>
This commit just addresses those warnings shown below.
Reference(s):
proc/sysinfo.c: In function `getrunners':
proc/sysinfo.c:491:26: warning: `%s' directive writing up to 255 bytes into a region of size 26 [-Wformat-overflow=]
491 | sprintf(tbuf, "/proc/%s/stat", ent->d_name);
| ^~
pgrep.c: In function `select_procs':
pgrep.c:591:11: warning: suggest explicit braces to avoid ambiguous `else' [-Wdangling-else]
591 | else if (opt_older)
| ^
Signed-off-by: Jim Warner <james.warner@comcast.net>
This patch just repositions some .PP macros so they'll
immediately precede the paragraphs to which they apply
rather than a comment line used as a visual separator.
[ ok we also update the document date to 'July 2020' ]
Signed-off-by: Jim Warner <james.warner@comcast.net>
This commit addresses the errors/warnings shown below.
Reference(s):
ERROR: skipping end of block that is not open: RE
WARNING: skipping paragraph macro: sp after PP
WARNING: skipping paragraph macro: PP empty
Signed-off-by: Jim Warner <james.warner@comcast.net>
This commit only eliminates two 'nop' instructions and
one 'jmp' instruction. However, it makes that C source
code look a little bit prettier than it looked before.
[ and yes, some unnecessary parenthesis were used to ]
[ force an alignment of some related lines. it costs ]
[ us nothing in extra code yet helps in readability. ]
Signed-off-by: Jim Warner <james.warner@comcast.net>
This patch eliminates one variable which resulted in a
corresponding elimination of three 'mov' instructions.
[ that was 6 bytes per 'mov' for a total of 18 bytes ]
Signed-off-by: Jim Warner <james.warner@comcast.net>
vmstat - align wording with proc manpage to clarify ambiguities (rhbz#1796043)
watch - manpage presumes ntp tools are present by default (which they're not on rpm and deb distros, rhbz#1583669)
We won't go as far as the merge request shown below in
increasing buffer size, but we'll reduce substantially
total iterations while growing it to achieve one read.
[ and this seems in line with what was recently done ]
[ to accommodate the massively parallel environments ]
[ thru 2 abreast ('4') and combined cpus ('!') modes ]
Reference(s:
https://gitlab.com/procps-ng/procps/-/merge_requests/105
Signed-off-by: Jim Warner <james.warner@comcast.net>
