List, Query, Manipulate System Processes
ps implements an API to query and manipulate system processes. Most of its code is based on the psutil Python package.
- Installation
- Supported platforms
- Listing all processes
- Process API
- Finished and zombie processes
- Pid reuse
- Recipes
- Code of Conduct
- License
You can install the released version of ps from CRAN with:
install.packages("ps")library(ps)
library(pillar) # nicer printing of data framesps currently supports Windows (from Vista), macOS and Linux systems. On
unsupported platforms the package can be installed and loaded, but all
of its functions fail with an error of class "not_implemented".
ps_pids() returns all process ids on the system. This can be useful to
iterate over all processes.
ps_pids()[1:20]## [1] 0 1 299 300 302 303 304 306 308 310 311 314 316 319 323 324 325 326 329 330
ps() returns a data frame, with data about each process. It contains a
handle to each process, in the ps_handle column, you can use these to
perform more queries on the processes.
ps()## # A data frame: 445 × 11
## pid ppid name username status user system rss vms created
## * <int> <int> <chr> <chr> <chr> <dbl> <dbl> <dbl> <dbl> <dttm>
## 1 28286 24879 R gaborcs… runni… 9.29e-3 1.29e-3 1.39e8 4.19e11 2022-06-17 11:08:04
## 2 28115 552 Google Chrome… gaborcs… runni… 1.19e-3 3.95e-4 6.32e7 4.61e11 2022-06-17 11:07:01
## 3 27238 1 com.apple.iCl… gaborcs… runni… 1.94e-3 1.13e-3 8.80e6 4.18e11 2022-06-17 11:03:47
## 4 27008 552 Google Chrome… gaborcs… runni… 1.15e-2 2.54e-3 1.11e8 4.61e11 2022-06-17 11:03:08
## 5 25835 25439 R gaborcs… runni… 2.49e-2 6.02e-3 1.45e8 4.19e11 2022-06-17 10:57:41
## 6 25771 25439 zsh gaborcs… runni… 3.11e-5 1.55e-4 3.42e6 4.19e11 2022-06-17 10:57:40
## 7 25439 25438 zsh gaborcs… runni… 2.48e-3 1.30e-3 1.39e7 4.19e11 2022-06-17 10:57:39
## 8 25438 635 login gaborcs… runni… NA NA NA NA 2022-06-17 10:57:39
## 9 25386 24879 Emacs-arm64-1… gaborcs… runni… 9.98e-1 1.52e-1 3.07e8 4.20e11 2022-06-17 10:57:30
## 10 25211 24879 zsh gaborcs… runni… 6.82e-4 2.85e-3 3.54e6 4.19e11 2022-06-17 10:57:08
## # … with 435 more rows, and 1 more variable: ps_handle <I<list>>
This is a short summary of the API. Please see the documentation of the various methods for details, in particular regarding handles to finished processes and pid reuse. See also “Finished and zombie processes” and “pid reuse” below.
ps_handle(pid) creates a process handle for the supplied process id.
If pid is omitted, a handle to the calling process is returned:
p <- ps_handle()
p## <ps::ps_handle> PID=28286, NAME=R, AT=2022-06-17 11:08:04
ps_pid(p) returns the pid of the process.
ps_pid(p)## [1] 28286
ps_create_time() returns the creation time of the process (according
to the OS).
ps_create_time(p)## [1] "2022-06-17 11:08:04 GMT"
The process id and the creation time uniquely identify a process in a system. ps uses them to make sure that it reports information about, and manipulates the correct process.
ps_is_running(p) returns whether p is still running. It handles pid
reuse safely.
ps_is_running(p)## [1] TRUE
ps_ppid(p) returns the pid of the parent of p.
ps_ppid(p)## [1] 24879
ps_parent(p) returns a process handle to the parent process of p.
ps_parent(p)## <ps::ps_handle> PID=24879, NAME=zsh, AT=2022-06-17 10:57:07
ps_name(p) returns the name of the program p is running.
ps_name(p)## [1] "R"
ps_exe(p) returns the full path to the executable the p is running.
ps_exe(p)## [1] "/Library/Frameworks/R.framework/Versions/4.2-arm64/Resources/bin/exec/R"
ps_cmdline(p) returns the command line (executable and arguments) of
p.
ps_cmdline(p)## [1] "/Library/Frameworks/R.framework/Versions/4.2-arm64/Resources/bin/exec/R"
## [2] "--no-echo"
## [3] "--no-restore"
## [4] "-e"
## [5] "rmarkdown::render(\"README.Rmd\")"
ps_status(p) returns the status of the process. Possible values are OS
dependent, but typically there is "running" and "stopped".
ps_status(p)## [1] "running"
ps_username(p) returns the name of the user the process belongs to.
ps_username(p)## [1] "gaborcsardi"
ps_uids(p) and ps_gids(p) return the real, effective and saved user
ids of the process. They are only implemented on POSIX systems.
if (ps_os_type()[["POSIX"]]) ps_uids(p)## real effective saved
## 501 501 501
if (ps_os_type()[["POSIX"]]) ps_gids(p)## real effective saved
## 20 20 20
ps_cwd(p) returns the current working directory of the process.
ps_cwd(p)## [1] "/Users/gaborcsardi/works/ps"
ps_terminal(p) returns the name of the terminal of the process, if
any. For processes without a terminal, and on Windows it returns
NA_character_.
ps_terminal(p)## [1] "/dev/ttys006"
ps_environ(p) returns the environment variables of the process.
ps_environ_raw(p) does the same, in a different form. Typically they
reflect the environment variables at the start of the process.
ps_environ(p)[c("TERM", "USER", "SHELL", "R_HOME")]## TERM xterm-256color
## USER gaborcsardi
## SHELL /bin/zsh
## R_HOME /Library/Frameworks/R.framework/Versions/4.2-arm64/Resources
ps_num_threads(p) returns the current number of threads of the
process.
ps_num_threads(p)## [1] 3
ps_cpu_times(p) returns the CPU times of the process, similarly to
proc.time().
ps_cpu_times(p)## user system children_user children_system
## 0.010692116 0.001444821 NA NA
ps_memory_info(p) returns memory usage information. See the manual for
details.
ps_memory_info(p)## rss vms pfaults pageins
## 148783104 419159621632 9884 0
ps_children(p) lists all child processes (potentially recursively) of
the current process.
ps_children(ps_parent(p))## [[1]]
## <ps::ps_handle> PID=25211, NAME=zsh, AT=2022-06-17 10:57:08
##
## [[2]]
## <ps::ps_handle> PID=25386, NAME=Emacs-arm64-11_2, AT=2022-06-17 10:57:30
##
## [[3]]
## <ps::ps_handle> PID=28286, NAME=R, AT=2022-06-17 11:08:04
ps_num_fds(p) returns the number of open file descriptors (handles on
Windows):
ps_num_fds(p)## [1] 4
f <- file(tmp <- tempfile(), "w")
ps_num_fds(p)## [1] 5
close(f)
unlink(tmp)ps_open_files(p) lists all open files:
ps_open_files(p)## # A data frame: 4 × 2
## fd path
## <int> <chr>
## 1 0 /dev/ttys006
## 2 1 /dev/ttys006
## 3 2 /dev/ttys006
## 4 3 /private/var/folders/ph/fpcmzfd16rgbbk8mxvy9m2_h0000gn/T/Rscript6e7e.sDuQan
f <- file(tmp <- tempfile(), "w")
ps_open_files(p)## # A data frame: 5 × 2
## fd path
## <int> <chr>
## 1 0 /dev/ttys006
## 2 1 /dev/ttys006
## 3 2 /dev/ttys006
## 4 3 /private/var/folders/ph/fpcmzfd16rgbbk8mxvy9m2_h0000gn/T/Rscript6e7e.sDuQan
## 5 4 /private/var/folders/ph/fpcmzfd16rgbbk8mxvy9m2_h0000gn/T/RtmpBQnIMy/file6e7e757f921d
close(f)
unlink(tmp)
ps_open_files(p)## # A data frame: 4 × 2
## fd path
## <int> <chr>
## 1 0 /dev/ttys006
## 2 1 /dev/ttys006
## 3 2 /dev/ttys006
## 4 3 /private/var/folders/ph/fpcmzfd16rgbbk8mxvy9m2_h0000gn/T/Rscript6e7e.sDuQan
ps_suspend(p) suspends (stops) the process. On POSIX it sends a
SIGSTOP signal. On Windows it stops all threads.
ps_resume(p) resumes the process. On POSIX it sends a SIGCONT signal.
On Windows it resumes all stopped threads.
ps_send_signal(p) sends a signal to the process. It is implemented on
POSIX systems only. It makes an effort to work around pid reuse.
ps_terminate(p) send SIGTERM to the process. On POSIX systems only.
ps_kill(p) terminates the process. Sends SIGKILL on POSIX systems,
uses TerminateProcess() on Windows. It make an effort to work around
pid reuse.
ps_interrupt(p) interrupts a process. It sends a SIGINT signal on
POSIX systems, and it can send a CTRL+C or a CTRL+BREAK event on
Windows.
ps handles finished and Zombie processes as much as possible.
The essential ps_pid(), ps_create_time(), ps_is_running()
functions and the format() and print() methods work for all
processes, including finished and zombie processes. Other functions fail
with an error of class "no_such_process" for finished processes.
The ps_ppid(), ps_parent(), ps_children(), ps_name(),
ps_status(), ps_username(), ps_uids(), ps_gids(),
ps_terminal(), ps_children() and the signal sending functions work
properly for zombie processes. Other functions fail with
"zombie_process" error.
ps functions handle pid reuse as well as technically possible.
The query functions never return information about the wrong process, even if the process has finished and its process id was re-assigned.
On Windows, the process manipulation functions never manipulate the wrong process.
On POSIX systems, this is technically impossible, it is not possible to send a signal to a process without creating a race condition. In ps the time window of the race condition is very small, a few microseconds, and the process would need to finish, and the OS would need to reuse its pid within this time window to create problems. This is very unlikely to happen.
In the spirit of psutil recipes.
Using ps() and dplyr:
library(dplyr)
find_procs_by_name <- function(name) {
ps() %>%
filter(name == !!name) %>%
pull(ps_handle)
}
find_procs_by_name("R")## [[1]]
## <ps::ps_handle> PID=28286, NAME=R, AT=2022-06-17 11:08:04
##
## [[2]]
## <ps::ps_handle> PID=25835, NAME=R, AT=2022-06-17 10:57:41
##
## [[3]]
## <ps::ps_handle> PID=65603, NAME=R, AT=2022-06-17 10:00:56
Without creating the full table of processes:
find_procs_by_name <- function(name) {
procs <- lapply(ps_pids(), function(p) {
tryCatch({
h <- ps_handle(p)
if (ps_name(h) == name) h else NULL },
no_such_process = function(e) NULL,
access_denied = function(e) NULL
)
})
procs[!vapply(procs, is.null, logical(1))]
}
find_procs_by_name("R")## [[1]]
## <ps::ps_handle> PID=25835, NAME=R, AT=2022-06-17 10:57:41
##
## [[2]]
## <ps::ps_handle> PID=28286, NAME=R, AT=2022-06-17 11:08:04
##
## [[3]]
## <ps::ps_handle> PID=65603, NAME=R, AT=2022-06-17 10:00:56
On POSIX, there is no good way to wait for non-child processes to finish, so we need to write a sleep-wait loop to do it. (On Windows, and BSD systems, including macOS, there are better solutions.)
as_secs <- function(x) as.numeric(x, units = "secs")
wait_for_process <- function(proc, timeout = Inf, sleep = 0.1) {
sleep <- as_secs(sleep)
deadline <- Sys.time() + timeout
while (ps_is_running(proc) && (timeout == Inf || Sys.time() < deadline)) {
to <- min(as_secs(deadline - Sys.time()), sleep)
Sys.sleep(to)
}
! ps_is_running(proc)
}
px <- processx::process$new("sleep", "2")
p <- ps_handle(px$get_pid())
wait_for_process(p, 1)## [1] FALSE
wait_for_process(p)## [1] TRUE
This is similar, but we need to wait on all processes in a loop.
wait_for_processes <- function(procs, timeout = Inf) {
gone <- list()
alive <- procs
deadline <- Sys.time() + timeout
check_gone <- function(proc, timeout) {
proc_gone <- wait_for_process(proc, timeout = timeout)
if (proc_gone) {
gone <<- c(gone, list(proc))
alive <<- setdiff(alive, list(proc))
}
}
while (length(alive)) {
if (timeout <= 0) break
for (proc in alive) {
max_timeout <- 1 / length(alive)
if (timeout != Inf) {
timeout <- min(as_secs(deadline - Sys.time()), max_timeout)
if (timeout <= 0) break
check_gone(proc, timeout)
} else {
check_gone(proc, max_timeout)
}
}
}
list(gone = gone, alive = alive)
}
px1 <- processx::process$new("sleep", "10")
px2 <- processx::process$new("sleep", "10")
px3 <- processx::process$new("sleep", "1")
px4 <- processx::process$new("sleep", "1")
p1 <- ps_handle(px1$get_pid())
p2 <- ps_handle(px2$get_pid())
p3 <- ps_handle(px3$get_pid())
p4 <- ps_handle(px4$get_pid())
wait_for_processes(list(p1, p2, p3, p4), timeout = 2)## $gone
## $gone[[1]]
## <ps::ps_handle> PID=28305, NAME=???, AT=2022-06-17 11:08:06
##
## $gone[[2]]
## <ps::ps_handle> PID=28304, NAME=???, AT=2022-06-17 11:08:06
##
##
## $alive
## $alive[[1]]
## <ps::ps_handle> PID=28302, NAME=sleep, AT=2022-06-17 11:08:06
##
## $alive[[2]]
## <ps::ps_handle> PID=28303, NAME=sleep, AT=2022-06-17 11:08:06
This sends a signal, so it’ll only work on Unix. Use ps_kill() instead
of ps_send_signal() on Windows.
kill_proc_tree <- function(pid, sig = signals()$SIGTERM,
include_parent = TRUE) {
if (pid == Sys.getpid() && include_parent) stop("I refuse to kill myself")
parent <- ps_handle(pid)
children <- ps_children(parent, recursive = TRUE)
if (include_parent) children <- c(children, parent)
for (p in children) ps_send_signal(p, sig)
wait_for_processes(children, timeout = 0.1)
}
p1 <- processx::process$new("sleep", "10")
p2 <- processx::process$new("sleep", "10")
p3 <- processx::process$new("sleep", "10")
kill_proc_tree(Sys.getpid(), include_parent = FALSE)## $gone
## $gone[[1]]
## <ps::ps_handle> PID=28302, NAME=???, AT=2022-06-17 11:08:06
##
##
## $alive
## $alive[[1]]
## <ps::ps_handle> PID=28303, NAME=???, AT=2022-06-17 11:08:06
##
## $alive[[2]]
## <ps::ps_handle> PID=28309, NAME=???, AT=2022-06-17 11:08:08
##
## $alive[[3]]
## <ps::ps_handle> PID=28310, NAME=???, AT=2022-06-17 11:08:08
##
## $alive[[4]]
## <ps::ps_handle> PID=28311, NAME=???, AT=2022-06-17 11:08:09
Note, that some R IDEs, including RStudio, run a multithreaded R
process, and other threads may start processes as well.
reap_children() will clean up all these as well, potentially causing
the IDE to misbehave or crash.
reap_children <- function(timeout = 3) {
procs <- ps_children(ps_handle())
## SIGTERM
lapply(procs, ps_terminate)
ga <- wait_for_processes(procs, timeout = timeout)
## SIGKILL to the survivers
if (length(ga$alive)) lapply(ga$alive, ps_kill)
ga2 <- wait_for_processes(ga$alive, timeout = timeout)
## Some might still survive
list(gone = c(ga$gone, ga2$gone), alive = ga2$alive)
}
pxs <- replicate(3, processx::process$new("sleep", "3"))
reap_children()## $gone
## $gone[[1]]
## <ps::ps_handle> PID=28312, NAME=???, AT=2022-06-17 11:08:09
##
## $gone[[2]]
## <ps::ps_handle> PID=28313, NAME=???, AT=2022-06-17 11:08:09
##
## $gone[[3]]
## <ps::ps_handle> PID=28314, NAME=???, AT=2022-06-17 11:08:09
##
##
## $alive
## list()
Process name ending with “sh”:
ps() %>%
filter(grepl("sh$", name))## # A data frame: 15 × 11
## pid ppid name username status user system rss vms created ps_handle
## <int> <int> <chr> <chr> <chr> <dbl> <dbl> <dbl> <dbl> <dttm> <I<list>>
## 1 25771 25439 zsh gaborcs… runni… 3.11e-5 1.55e-4 3.42e6 4.19e11 2022-06-17 10:57:40 <ps_handl>
## 2 25439 25438 zsh gaborcs… runni… 2.48e-3 1.30e-3 1.39e7 4.19e11 2022-06-17 10:57:39 <ps_handl>
## 3 25211 24879 zsh gaborcs… runni… 6.82e-4 2.85e-3 3.54e6 4.19e11 2022-06-17 10:57:08 <ps_handl>
## 4 24879 24878 zsh gaborcs… runni… 8.86e-3 6.64e-3 1.53e7 4.19e11 2022-06-17 10:57:07 <ps_handl>
## 5 65545 65211 zsh gaborcs… runni… 3.22e-5 1.54e-4 1.03e6 4.19e11 2022-06-17 10:00:55 <ps_handl>
## 6 65211 65207 zsh gaborcs… runni… 2.27e-3 1.23e-3 1.87e6 4.19e11 2022-06-17 10:00:55 <ps_handl>
## 7 64395 64394 bash gaborcs… runni… 6.15e-5 1.92e-4 1.08e6 4.18e11 2022-06-17 10:00:46 <ps_handl>
## 8 63945 63613 zsh gaborcs… runni… 7.52e-5 3.53e-4 2.00e6 4.19e11 2022-06-17 10:00:28 <ps_handl>
## 9 63613 63612 zsh gaborcs… runni… 3.48e-3 2.36e-3 9.63e6 4.19e11 2022-06-17 10:00:27 <ps_handl>
## 10 63097 62765 zsh gaborcs… runni… 1.05e-4 4.88e-4 2.03e6 4.19e11 2022-06-17 09:57:05 <ps_handl>
## 11 62765 62764 zsh gaborcs… runni… 4.12e-3 3.52e-3 1.04e7 4.19e11 2022-06-17 09:57:04 <ps_handl>
## 12 54571 54239 zsh gaborcs… runni… 7.58e-4 3.27e-3 2.64e6 4.19e11 2022-06-17 09:41:33 <ps_handl>
## 13 54239 54238 zsh gaborcs… runni… 1.53e-2 1.27e-2 1.14e7 4.19e11 2022-06-17 09:41:32 <ps_handl>
## 14 1243 1 Report… gaborcs… runni… 1.59e-2 1.36e-2 6.75e6 4.18e11 2022-06-15 17:42:09 <ps_handl>
## 15 1063 1 Plash gaborcs… runni… 6.35e-2 5.96e-2 3.88e7 4.20e11 2022-06-15 17:41:45 <ps_handl>
Processes owned by user:
ps() %>%
filter(username == Sys.info()[["user"]]) %>%
select(pid, name)## # A data frame: 276 × 2
## pid name
## <int> <chr>
## 1 28308 Google Chrome Helper (Renderer)
## 2 28307 Google Chrome Helper (Renderer)
## 3 28306 Google Chrome Helper (Renderer)
## 4 28286 R
## 5 28115 Google Chrome Helper (Renderer)
## 6 27238 com.apple.iCloudHelper
## 7 27008 Google Chrome Helper (Renderer)
## 8 25835 R
## 9 25771 zsh
## 10 25439 zsh
## # … with 266 more rows
Processes consuming more than 100MB of memory:
ps() %>%
filter(rss > 100 * 1024 * 1024)## # A data frame: 18 × 11
## pid ppid name username status user system rss vms created ps_handle
## <int> <int> <chr> <chr> <chr> <dbl> <dbl> <dbl> <dbl> <dttm> <I<list>>
## 1 28286 24879 R gaborcs… runni… 1.81e-2 5.89e-3 1.62e8 4.20e11 2022-06-17 11:08:04 <ps_handl>
## 2 28115 552 Google… gaborcs… runni… 2.28e-3 6.07e-4 1.07e8 4.66e11 2022-06-17 11:07:01 <ps_handl>
## 3 27008 552 Google… gaborcs… runni… 1.15e-2 2.54e-3 1.11e8 4.61e11 2022-06-17 11:03:08 <ps_handl>
## 4 25835 25439 R gaborcs… runni… 2.49e-2 6.03e-3 1.45e8 4.19e11 2022-06-17 10:57:41 <ps_handl>
## 5 25386 24879 Emacs-… gaborcs… runni… 9.99e-1 1.52e-1 3.07e8 4.20e11 2022-06-17 10:57:30 <ps_handl>
## 6 22559 552 Google… gaborcs… runni… 1.01e-1 1.36e-2 2.93e8 4.61e11 2022-06-17 10:53:21 <ps_handl>
## 7 20177 552 Google… gaborcs… runni… 9.79e-2 1.85e-2 1.50e8 4.62e11 2022-06-17 10:19:03 <ps_handl>
## 8 20125 1 Amazon… gaborcs… runni… 5.65e-1 1.13e-1 2.09e8 3.79e10 2022-06-17 10:17:38 <ps_handl>
## 9 62712 54239 Emacs-… gaborcs… runni… 3.07e-1 4.55e-2 1.13e8 4.19e11 2022-06-17 09:56:55 <ps_handl>
## 10 62557 552 Google… gaborcs… runni… 3.54e-1 6.36e-2 1.76e8 4.62e11 2022-06-17 09:56:06 <ps_handl>
## 11 59570 552 Google… gaborcs… runni… 5.44e-2 1.43e-2 1.32e8 4.66e11 2022-06-17 09:47:10 <ps_handl>
## 12 51439 552 Google… gaborcs… runni… 1.28e+0 1.54e-1 2.88e8 4.66e11 2022-06-17 09:36:51 <ps_handl>
## 13 1274 552 Google… gaborcs… runni… 1.08e+1 1.52e+0 5.44e8 4.66e11 2022-06-15 17:42:51 <ps_handl>
## 14 1019 552 Google… gaborcs… runni… 2.53e+0 6.05e-1 1.28e8 4.72e11 2022-06-15 17:41:44 <ps_handl>
## 15 1017 552 Google… gaborcs… runni… 2.39e+0 6.77e-1 2.26e8 4.61e11 2022-06-15 17:41:44 <ps_handl>
## 16 614 552 Google… gaborcs… runni… 5.76e+1 3.46e+1 2.83e8 4.53e11 2022-06-15 17:41:42 <ps_handl>
## 17 552 1 Google… gaborcs… runni… 3.96e+1 1.34e+1 5.25e8 4.53e11 2022-06-15 17:41:40 <ps_handl>
## 18 544 1 iTerm2 gaborcs… runni… 2.29e+1 3.58e+0 5.36e8 4.21e11 2022-06-15 17:41:40 <ps_handl>
Top 3 memory consuming processes:
ps() %>%
top_n(3, rss) %>%
arrange(desc(rss))## # A data frame: 3 × 11
## pid ppid name username status user system rss vms created ps_handle
## <int> <int> <chr> <chr> <chr> <dbl> <dbl> <dbl> <dbl> <dttm> <I<list>>
## 1 544 1 iTerm2 gaborcs… runni… 22.9 3.58 5.51e8 4.21e11 2022-06-15 17:41:40 <ps_handl>
## 2 1274 552 Google Chr… gaborcs… runni… 10.8 1.52 5.44e8 4.66e11 2022-06-15 17:42:51 <ps_handl>
## 3 552 1 Google Chr… gaborcs… runni… 39.6 13.4 5.25e8 4.53e11 2022-06-15 17:41:40 <ps_handl>
Top 3 processes which consumed the most CPU time:
ps() %>%
mutate(cpu_time = user + system) %>%
top_n(3, cpu_time) %>%
arrange(desc(cpu_time)) %>%
select(pid, name, cpu_time)## # A data frame: 3 × 3
## pid name cpu_time
## <int> <chr> <dbl>
## 1 614 Google Chrome Helper (GPU) 92.2
## 2 552 Google Chrome 53.0
## 3 544 iTerm2 26.5
Please note that the ps project is released with a Contributor Code of Conduct. By contributing to this project, you agree to abide by its terms.
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