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 51 52 55 56 57 59 62 63 64 65 70 74 76 77 82 83 85 87ps() 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: 386 x 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 98737 1 quic… gaborcs… runni… 0.0425 0.0200 2.48e7 3.09e9 2018-07-24 09:41:40 <S3: ps_…
## 2 98327 1 mdwo… _spotli… runni… NA NA NA NA 2018-07-24 09:39:02 <S3: ps_…
## 3 98318 3718 Goog… gaborcs… runni… 0.0650 0.0276 4.62e7 3.36e9 2018-07-24 09:37:30 <S3: ps_…
## 4 96820 3718 Goog… gaborcs… runni… 0.114 0.0618 5.14e7 3.38e9 2018-07-24 09:10:29 <S3: ps_…
## 5 96817 3718 Goog… gaborcs… runni… 0.953 0.163 1.14e8 3.56e9 2018-07-24 09:09:42 <S3: ps_…
## 6 96816 3718 Goog… gaborcs… runni… 1.58 0.265 1.45e8 3.66e9 2018-07-24 09:09:37 <S3: ps_…
## 7 96809 3718 Goog… gaborcs… runni… 0.865 0.158 1.41e8 3.59e9 2018-07-24 09:09:34 <S3: ps_…
## 8 96680 3718 Goog… gaborcs… runni… 12.5 1.86 2.02e8 3.54e9 2018-07-24 08:41:27 <S3: ps_…
## 9 96679 3718 Goog… gaborcs… runni… 26.5 5.92 1.48e8 3.58e9 2018-07-24 08:41:27 <S3: ps_…
## 10 96678 3718 Goog… gaborcs… runni… 171. 16.1 2.72e8 3.70e9 2018-07-24 08:41:26 <S3: ps_…
## # ... with 376 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=93065, NAME=R, AT=2018-07-23 17:27:55ps_pid(p) returns the pid of the process.
## [1] 93065ps_create_time() returns the creation time of the process (according to the OS).
## [1] "2018-07-23 17:27:55 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] 90285ps_parent(p) returns a process handle to the parent process of p.
## <ps::ps_handle> PID=90285, NAME=zsh, AT=2018-07-23 16:15:32ps_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/3.5/Resources/bin/exec/R"ps_cmdline(p) returns the command line (executable and arguments) of p.
## [1] "/Library/Frameworks/R.framework/Resources/bin/exec/R"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] "/dev/ttys003"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.
## TERM xterm-256color
## USER gaborcsardi
## SHELL /bin/zsh
## R_HOME /Library/Frameworks/R.framework/Resourcesps_num_threads(p) returns the current number of threads of the process.
## [1] 4ps_cpu_times(p) returns the CPU times of the process, similarly to proc.time().
## user system childen_user children_system
## 8.023153 1.288586 NA NAps_memory_info(p) returns memory usage information. See the manual for details.
## rss vms pfaults pageins
## 132501504 2719563776 318180 1028ps_children(p) lists all child processes (potentially recuirsively) of the current process.
## [[1]]
## <ps::ps_handle> PID=90291, NAME=zsh, AT=2018-07-23 16:15:32
##
## [[2]]
## <ps::ps_handle> PID=93065, NAME=R, AT=2018-07-23 17:27:55ps_num_fds(p) returns the number of open file descriptors (handles on Windows):
## [1] 3## [1] 4ps_open_files(p) lists all open files:
## # A tibble: 3 x 2
## fd path
## <int> <chr>
## 1 0 /dev/ttys003
## 2 1 /dev/ttys003
## 3 2 /dev/ttys003## # A tibble: 4 x 2
## fd path
## <int> <chr>
## 1 0 /dev/ttys003
## 2 1 /dev/ttys003
## 3 2 /dev/ttys003
## 4 3 /private/var/folders/59/0gkmw1yj2w7bf2dfc3jznv5w0000gn/T/RtmpxkerNt/file16b892817efc1## # A tibble: 3 x 2
## fd path
## <int> <chr>
## 1 0 /dev/ttys003
## 2 1 /dev/ttys003
## 3 2 /dev/ttys003ps_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=93065, NAME=R, AT=2018-07-23 17:27:55
##
## [[2]]
## <ps::ps_handle> PID=86811, NAME=R, AT=2018-07-23 13:22:12
##
## [[3]]
## <ps::ps_handle> PID=79811, NAME=R, AT=2018-07-23 12:15:12Without 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=79811, NAME=R, AT=2018-07-23 12:15:12
##
## [[2]]
## <ps::ps_handle> PID=86811, NAME=R, AT=2018-07-23 13:22:12
##
## [[3]]
## <ps::ps_handle> PID=93065, NAME=R, AT=2018-07-23 17:27:55On 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=98990, NAME=???, AT=2018-07-24 09:45:30
##
## $gone[[2]]
## <ps::ps_handle> PID=98989, NAME=???, AT=2018-07-24 09:45:30
##
##
## $alive
## $alive[[1]]
## <ps::ps_handle> PID=98987, NAME=sleep, AT=2018-07-24 09:45:30
##
## $alive[[2]]
## <ps::ps_handle> PID=98988, NAME=sleep, AT=2018-07-24 09:45:30This sends a signal, so it’ll only work on Unix. Use ps_kill() instead of ps_send_signal() on Windows.
kill_proc_tree <- function(pid, sig = signals()$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=98987, NAME=???, AT=2018-07-24 09:45:30
##
##
## $alive
## $alive[[1]]
## <ps::ps_handle> PID=98988, NAME=???, AT=2018-07-24 09:45:30
##
## $alive[[2]]
## <ps::ps_handle> PID=98991, NAME=???, AT=2018-07-24 09:45:32
##
## $alive[[3]]
## <ps::ps_handle> PID=98992, NAME=???, AT=2018-07-24 09:45:32
##
## $alive[[4]]
## <ps::ps_handle> PID=98993, NAME=???, AT=2018-07-24 09:45:32Note, that some R IDEs, including RStudio, run a multithreaded R process, and other threads may start processes as well. reap_children() will clean up all these as well, potentially causing the IDE to misbehave or crash.
reap_children <- function(timeout = 3) {
procs <- ps_children(ps_handle())
## SIGTERM
lapply(procs, ps_terminate)
ga <- wait_for_processes(procs, timeout = timeout)
## SIGKILL to the survivers
if (length(ga$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=98994, NAME=???, AT=2018-07-24 09:45:32
##
## $gone[[2]]
## <ps::ps_handle> PID=98995, NAME=???, AT=2018-07-24 09:45:32
##
## $gone[[3]]
## <ps::ps_handle> PID=98996, NAME=???, AT=2018-07-24 09:45:32
##
##
## $alive
## list()Process name ending with “sh”:
## # A tibble: 21 x 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 94582 94576 zsh gaborcsa… running 0.00595 0.00875 8.19e3 2.52e9 2018-07-23 21:06:28 <S3: ps_h…
## 2 94576 94575 zsh gaborcsa… running 0.243 0.111 1.64e4 2.52e9 2018-07-23 21:06:28 <S3: ps_h…
## 3 93603 93597 zsh gaborcsa… running 0.00659 0.00973 8.19e3 2.52e9 2018-07-23 17:44:33 <S3: ps_h…
## 4 93597 93596 zsh gaborcsa… running 0.303 0.133 1.64e4 2.52e9 2018-07-23 17:44:33 <S3: ps_h…
## 5 93482 93476 zsh gaborcsa… running 0.00524 0.00804 8.19e3 2.52e9 2018-07-23 17:40:47 <S3: ps_h…
## 6 93476 93475 zsh gaborcsa… running 0.384 0.149 1.64e4 2.52e9 2018-07-23 17:40:46 <S3: ps_h…
## 7 90291 90285 zsh gaborcsa… running 0.0118 0.0175 8.19e3 2.52e9 2018-07-23 16:15:32 <S3: ps_h…
## 8 90285 90284 zsh gaborcsa… running 0.256 0.119 1.64e4 2.52e9 2018-07-23 16:15:32 <S3: ps_h…
## 9 90057 90051 zsh gaborcsa… running 0.0290 0.0514 1.27e6 2.52e9 2018-07-23 16:14:26 <S3: ps_h…
## 10 90051 90050 zsh gaborcsa… running 0.609 0.281 7.11e6 2.52e9 2018-07-23 16:14:26 <S3: ps_h…
## # ... with 11 more rowsProcesses owned by user:
## # A tibble: 258 x 2
## pid name
## <int> <chr>
## 1 98737 quicklookd
## 2 98318 Google Chrome Helper
## 3 96820 Google Chrome Helper
## 4 96817 Google Chrome Helper
## 5 96816 Google Chrome Helper
## 6 96809 Google Chrome Helper
## 7 96680 Google Chrome Helper
## 8 96679 Google Chrome Helper
## 9 96678 Google Chrome Helper
## 10 96677 Google Chrome Helper
## # ... with 248 more rowsProcesses consuming more than 100MB of memory:
## # A tibble: 16 x 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 96817 3718 Google… gaborcsa… runni… 9.53e-1 1.63e-1 1.14e8 3.56e9 2018-07-24 09:09:42 <S3: ps_…
## 2 96816 3718 Google… gaborcsa… runni… 1.58e+0 2.65e-1 1.45e8 3.66e9 2018-07-24 09:09:37 <S3: ps_…
## 3 96809 3718 Google… gaborcsa… runni… 8.65e-1 1.58e-1 1.41e8 3.59e9 2018-07-24 09:09:34 <S3: ps_…
## 4 96680 3718 Google… gaborcsa… runni… 1.25e+1 1.86e+0 2.02e8 3.54e9 2018-07-24 08:41:27 <S3: ps_…
## 5 96679 3718 Google… gaborcsa… runni… 2.65e+1 5.93e+0 1.48e8 3.58e9 2018-07-24 08:41:27 <S3: ps_…
## 6 96678 3718 Google… gaborcsa… runni… 1.71e+2 1.61e+1 2.72e8 3.70e9 2018-07-24 08:41:26 <S3: ps_…
## 7 96674 3718 Google… gaborcsa… runni… 1.04e+1 2.29e+0 1.79e8 3.63e9 2018-07-24 08:41:26 <S3: ps_…
## 8 96673 3718 Google… gaborcsa… runni… 1.06e+2 1.55e+1 1.71e8 3.62e9 2018-07-24 08:41:25 <S3: ps_…
## 9 95883 95882 Virtua… gaborcsa… runni… 2.03e+3 1.32e+3 4.73e9 7.53e9 2018-07-23 22:50:14 <S3: ps_…
## 10 93065 90285 R gaborcsa… runni… 8.77e+0 1.53e+0 1.33e8 2.75e9 2018-07-23 17:27:55 <S3: ps_…
## 11 90173 90051 Emacs-… gaborcsa… runni… 3.18e+2 5.53e+1 1.99e8 2.89e9 2018-07-23 16:14:37 <S3: ps_…
## 12 92685 3718 Google… gaborcsa… runni… 1.20e+3 1.48e+2 5.32e8 4.89e9 2018-07-22 07:19:55 <S3: ps_…
## 13 35685 3718 Google… gaborcsa… runni… 7.01e+2 7.20e+1 3.67e8 4.15e9 2018-07-19 08:42:23 <S3: ps_…
## 14 3722 3718 Google… gaborcsa… runni… 2.84e+3 1.36e+3 1.44e8 3.40e9 2018-07-17 21:26:21 <S3: ps_…
## 15 3718 1 Google… gaborcsa… runni… 1.14e+4 3.85e+3 4.69e8 4.44e9 2018-07-17 21:26:21 <S3: ps_…
## 16 722 1 iTerm2 gaborcsa… runni… 6.36e+3 1.07e+3 2.24e8 3.59e9 2018-07-17 20:26:27 <S3: ps_…Top 3 memory consuming processes:
## # A tibble: 3 x 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 95883 95882 Virtual… gaborcsa… running 2034. 1320. 4.73e9 7.53e9 2018-07-23 22:50:14 <S3: ps_h…
## 2 92685 3718 Google … gaborcsa… running 1201. 148. 5.32e8 4.89e9 2018-07-22 07:19:55 <S3: ps_h…
## 3 3718 1 Google … gaborcsa… running 11431. 3848. 4.69e8 4.44e9 2018-07-17 21:26:21 <S3: ps_h…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 x 3
## pid name cpu_time
## <int> <chr> <dbl>
## 1 40706 com.docker.hyperkit 31685.
## 2 38474 Google Chrome Helper (GPU) 23568.
## 3 38466 Google Chrome 20589.Please note that this project is released with a Contributor Code of Conduct. By participating in this project you agree to abide by its terms.
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