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.
You can install the released version of ps from CRAN with:
ps 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.
## [1] 0 1 370 371 372 497 498 500 501 502 504 506 508 509 512 517 521 523 524 528ps() returns a data frame (tibble if you have the tibble package available), 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.
## # A tibble: 523 × 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 32549 1 MRT gaborcs… runni… 2.16e-4 3.24e-4 5.59e6 4.18e11 2022-04-23 14:53:35 <ps_handl>
## 2 32537 28512 R gaborcs… runni… 1.04e-2 1.47e-3 1.53e8 4.19e11 2022-04-23 14:53:34 <ps_handl>
## 3 32494 1 mdwork… gaborcs… runni… 1.13e-3 3.82e-4 2.09e7 4.18e11 2022-04-23 14:53:33 <ps_handl>
## 4 32487 1 mdwork… gaborcs… runni… 7.54e-4 4.63e-4 1.38e7 4.18e11 2022-04-23 14:53:33 <ps_handl>
## 5 32486 1 mdwork… gaborcs… runni… 1.18e-3 5.54e-4 2.09e7 4.18e11 2022-04-23 14:53:33 <ps_handl>
## 6 32446 3845 Google… gaborcs… runni… 1.14e-3 4.12e-4 5.87e7 4.61e11 2022-04-23 14:53:20 <ps_handl>
## 7 32445 3845 Google… gaborcs… runni… 4.81e-4 1.91e-4 4.05e7 4.57e11 2022-04-23 14:53:17 <ps_handl>
## 8 32442 3845 Google… gaborcs… runni… 6.10e-2 6.27e-3 2.38e8 4.62e11 2022-04-23 14:53:17 <ps_handl>
## 9 32438 3845 Google… gaborcs… runni… 1.61e-3 5.20e-4 8.13e7 4.61e11 2022-04-23 14:52:57 <ps_handl>
## 10 32416 1 mdwork… gaborcs… runni… 1.50e-3 6.43e-4 2.06e7 4.18e11 2022-04-23 14:52:07 <ps_handl>
## # … with 513 more rowsThis 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:
## <ps::ps_handle> PID=32537, NAME=R, AT=2022-04-23 14:53:34ps_pid(p) returns the pid of the process.
## [1] 32537ps_create_time() returns the creation time of the process (according to the OS).
## [1] "2022-04-23 14:53:34 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.
## [1] TRUEps_ppid(p) returns the pid of the parent of p.
## [1] 28512ps_parent(p) returns a process handle to the parent process of p.
## <ps::ps_handle> PID=28512, NAME=R, AT=2022-04-23 12:33:17ps_name(p) returns the name of the program p is running.
## [1] "R"ps_exe(p) returns the full path to the executable the p is running.
## [1] "/Library/Frameworks/R.framework/Versions/4.1-arm64/Resources/bin/exec/R"ps_cmdline(p) returns the command line (executable and arguments) of p.
## [1] "/Library/Frameworks/R.framework/Versions/4.1-arm64/Resources/bin/exec/R"
## [2] "--slave"
## [3] "--no-save"
## [4] "--no-restore"
## [5] "-f"
## [6] "/var/folders/ph/fpcmzfd16rgbbk8mxvy9m2_h0000gn/T//RtmpNW4j0T/callr-scr-6f607ecfcf18"ps_status(p) returns the status of the process. Possible values are OS dependent, but typically there is "running" and "stopped".
## [1] "running"ps_username(p) returns the name of the user the process belongs to.
## [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.
## real effective saved
## 501 501 501## real effective saved
## 20 20 20ps_cwd(p) returns the current working directory of the process.
## [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_.
## [1] NAps_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.
## TERM xterm-256color
## USER gaborcsardi
## SHELL /bin/zsh
## R_HOME /Library/Frameworks/R.framework/Versions/4.1-arm64/Resourcesps_num_threads(p) returns the current number of threads of the process.
## [1] 3ps_cpu_times(p) returns the CPU times of the process, similarly to proc.time().
## user system children_user children_system
## 0.011758996 0.001636022 NA NAps_memory_info(p) returns memory usage information. See the manual for details.
## rss vms pfaults pageins
## 161431552 419165847552 10659 70ps_children(p) lists all child processes (potentially recursively) of the current process.
## [[1]]
## <ps::ps_handle> PID=32537, NAME=R, AT=2022-04-23 14:53:34ps_num_fds(p) returns the number of open file descriptors (handles on Windows):
## [1] 4## [1] 5ps_open_files(p) lists all open files:
## # A tibble: 2 × 2
## fd path
## <int> <chr>
## 1 0 /dev/null
## 2 3 /private/var/folders/ph/fpcmzfd16rgbbk8mxvy9m2_h0000gn/T/RtmpNW4j0T/callr-scr-6f607ecfcf18## # A tibble: 3 × 2
## fd path
## <int> <chr>
## 1 0 /dev/null
## 2 3 /private/var/folders/ph/fpcmzfd16rgbbk8mxvy9m2_h0000gn/T/RtmpNW4j0T/callr-scr-6f607ecfcf18
## 3 4 /private/var/folders/ph/fpcmzfd16rgbbk8mxvy9m2_h0000gn/T/RtmpEihKx2/file7f194ed30fc9## # A tibble: 2 × 2
## fd path
## <int> <chr>
## 1 0 /dev/null
## 2 3 /private/var/folders/ph/fpcmzfd16rgbbk8mxvy9m2_h0000gn/T/RtmpNW4j0T/callr-scr-6f607ecfcf18ps_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=32537, NAME=R, AT=2022-04-23 14:53:34
##
## [[2]]
## <ps::ps_handle> PID=28512, NAME=R, AT=2022-04-23 12:33:17
##
## [[3]]
## <ps::ps_handle> PID=9278, NAME=R, AT=2022-04-19 09:56:57Without 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=9278, NAME=R, AT=2022-04-19 09:56:57
##
## [[2]]
## <ps::ps_handle> PID=28512, NAME=R, AT=2022-04-23 12:33:17
##
## [[3]]
## <ps::ps_handle> PID=32537, NAME=R, AT=2022-04-23 14:53:34On 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## [1] TRUEThis 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=32556, NAME=???, AT=2022-04-23 14:53:37
##
## $gone[[2]]
## <ps::ps_handle> PID=32555, NAME=???, AT=2022-04-23 14:53:37
##
##
## $alive
## $alive[[1]]
## <ps::ps_handle> PID=32553, NAME=sleep, AT=2022-04-23 14:53:37
##
## $alive[[2]]
## <ps::ps_handle> PID=32554, NAME=sleep, AT=2022-04-23 14:53:37This sends a signal, so it’ll only work on Unix. Use ps_kill() instead of ps_send_signal() on Windows.
kill_proc_tree <- function(pid, sig = signals()$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=32553, NAME=???, AT=2022-04-23 14:53:37
##
## $gone[[2]]
## <ps::ps_handle> PID=32554, NAME=???, AT=2022-04-23 14:53:37
##
## $gone[[3]]
## <ps::ps_handle> PID=32561, NAME=???, AT=2022-04-23 14:53:39
##
## $gone[[4]]
## <ps::ps_handle> PID=32562, NAME=???, AT=2022-04-23 14:53:39
##
## $gone[[5]]
## <ps::ps_handle> PID=32563, NAME=???, AT=2022-04-23 14:53:39
##
##
## $alive
## list()Note, that some R IDEs, including RStudio, run a multithreaded R process, and other threads may start processes as well. reap_children() will clean up all these as well, potentially causing the IDE to misbehave or crash.
reap_children <- function(timeout = 3) {
procs <- ps_children(ps_handle())
## SIGTERM
lapply(procs, ps_terminate)
ga <- wait_for_processes(procs, timeout = timeout)
## SIGKILL to the survivers
if (length(ga$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=32564, NAME=???, AT=2022-04-23 14:53:39
##
## $gone[[2]]
## <ps::ps_handle> PID=32565, NAME=???, AT=2022-04-23 14:53:39
##
## $gone[[3]]
## <ps::ps_handle> PID=32566, NAME=???, AT=2022-04-23 14:53:39
##
##
## $alive
## list()Process name ending with “sh”:
## # A tibble: 21 × 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 31628 31296 zsh gaborcsar… runni… 3.11e-5 1.59e-4 3.34e6 4.19e11 2022-04-23 14:46:16 <ps_handl>
## 2 31296 31295 zsh gaborcsar… runni… 2.21e-3 1.03e-3 1.17e7 4.19e11 2022-04-23 14:46:15 <ps_handl>
## 3 31176 30844 zsh gaborcsar… runni… 1.87e-4 8.07e-4 3.46e6 4.19e11 2022-04-23 14:45:56 <ps_handl>
## 4 30844 30843 zsh gaborcsar… runni… 3.14e-3 2.03e-3 1.26e7 4.19e11 2022-04-23 14:45:55 <ps_handl>
## 5 28331 27999 zsh gaborcsar… runni… 9.40e-5 4.45e-4 1.79e6 4.19e11 2022-04-23 12:32:09 <ps_handl>
## 6 27999 27998 zsh gaborcsar… runni… 2.91e-3 1.83e-3 8.00e6 4.19e11 2022-04-23 12:32:09 <ps_handl>
## 7 27624 27292 zsh gaborcsar… runni… 2.76e-5 1.55e-4 1.03e6 4.19e11 2022-04-23 12:09:06 <ps_handl>
## 8 27292 27291 zsh gaborcsar… runni… 2.38e-3 1.38e-3 1.87e6 4.19e11 2022-04-23 12:09:05 <ps_handl>
## 9 20941 20609 zsh gaborcsar… runni… 1.82e-5 1.03e-4 3.44e5 4.19e11 2022-04-22 14:30:13 <ps_handl>
## 10 20609 20608 zsh gaborcsar… runni… 2.26e-3 1.37e-3 7.54e5 4.19e11 2022-04-22 14:30:12 <ps_handl>
## # … with 11 more rowsProcesses owned by user:
## # A tibble: 309 × 2
## pid name
## <int> <chr>
## 1 32567 Google Chrome Helper (Renderer)
## 2 32558 Google Chrome Helper (Renderer)
## 3 32537 R
## 4 32494 mdworker_shared
## 5 32487 mdworker_shared
## 6 32486 mdworker_shared
## 7 32445 Google Chrome Helper
## 8 32442 Google Chrome Helper (Renderer)
## 9 32438 Google Chrome Helper (Renderer)
## 10 32416 mdworker_shared
## # … with 299 more rowsProcesses consuming more than 100MB of memory:
## # A tibble: 17 × 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 32558 3845 Google… gaborcs… runni… 8.41e-3 1.35e-3 1.91e8 4.66e11 2022-04-23 14:53:39 <ps_handl>
## 2 32537 28512 R gaborcs… runni… 1.95e-2 6.44e-3 1.81e8 4.20e11 2022-04-23 14:53:34 <ps_handl>
## 3 32442 3845 Google… gaborcs… runni… 6.14e-2 6.36e-3 2.38e8 4.62e11 2022-04-23 14:53:17 <ps_handl>
## 4 29432 1 Amazon… gaborcs… runni… 2.87e-1 5.92e-2 2.31e8 3.67e10 2022-04-23 14:38:33 <ps_handl>
## 5 28512 27999 R gaborcs… runni… 4.73e-2 8.86e-3 2.78e8 4.19e11 2022-04-23 12:33:17 <ps_handl>
## 6 28456 3845 Google… gaborcs… runni… 6.22e-2 1.02e-2 1.69e8 4.62e11 2022-04-23 12:32:21 <ps_handl>
## 7 25580 3845 Google… gaborcs… runni… 1.47e-1 2.85e-2 1.12e8 4.66e11 2022-04-23 11:19:18 <ps_handl>
## 8 25386 3845 Google… gaborcs… runni… 7.38e-1 1.00e-1 2.75e8 4.66e11 2022-04-23 11:05:43 <ps_handl>
## 9 8796 3845 Google… gaborcs… runni… 2.87e+0 6.11e-1 2.26e8 4.66e11 2022-04-22 10:56:48 <ps_handl>
## 10 3915 3845 Google… gaborcs… runni… 1.18e+1 1.38e+0 5.21e8 4.66e11 2022-04-22 07:40:30 <ps_handl>
## 11 3904 3845 Google… gaborcs… runni… 1.49e+0 4.16e-1 2.08e8 4.61e11 2022-04-22 07:40:27 <ps_handl>
## 12 3876 3845 Google… gaborcs… runni… 1.75e+0 4.14e-1 1.15e8 4.72e11 2022-04-22 07:40:24 <ps_handl>
## 13 3865 3845 Google… gaborcs… runni… 5.77e-1 1.49e-1 1.77e8 4.66e11 2022-04-22 07:40:21 <ps_handl>
## 14 3859 3845 Google… gaborcs… runni… 3.32e+1 1.94e+1 2.35e8 4.54e11 2022-04-22 07:40:21 <ps_handl>
## 15 3845 1 Google… gaborcs… runni… 2.71e+1 9.36e+0 5.18e8 4.53e11 2022-04-22 07:40:20 <ps_handl>
## 16 97901 94806 Emacs-… gaborcs… runni… 7.64e+0 1.12e+0 1.16e8 4.20e11 2022-04-19 08:35:44 <ps_handl>
## 17 14121 1 iTerm2 gaborcs… runni… 2.04e+2 3.82e+1 5.47e8 4.21e11 2022-04-03 23:28:13 <ps_handl>Top 3 memory consuming processes:
## # A tibble: 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 14121 1 iTerm2 gaborcs… runni… 204. 38.2 5.47e8 4.21e11 2022-04-03 23:28:13 <ps_handl>
## 2 3915 3845 Google Chr… gaborcs… runni… 11.8 1.38 5.21e8 4.66e11 2022-04-22 07:40:30 <ps_handl>
## 3 3845 1 Google Chr… gaborcs… runni… 27.1 9.36 4.85e8 4.53e11 2022-04-22 07:40:20 <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 tibble: 3 × 3
## pid name cpu_time
## <int> <chr> <dbl>
## 1 14121 iTerm2 242.
## 2 10419 keybase 102.
## 3 10367 Keybase Helper (GPU) 62.3Please 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.
MIT © RStudio