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")If you need the development version, install it with
pak::pak("r-lib/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 1125 1127 1129 1130 1133 1136 1138 1139 1144 1149 1153 1155 1156 1161 1164 1165 1166
## [20] 1167
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: 477 × 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 81068 1 mdwo… gaborcs… runni… 0.0377 0.0143 2.61e7 4.20e11 2024-09-01 09:39:46 <ps_handl>
## 2 81067 1 mdwo… gaborcs… runni… 0.0423 0.0133 2.19e7 4.20e11 2024-09-01 09:39:46 <ps_handl>
## 3 80413 1 mdwo… gaborcs… runni… 0.0717 0.0220 2.84e7 4.20e11 2024-09-01 09:39:27 <ps_handl>
## 4 80412 1 mdwo… gaborcs… runni… 0.0749 0.0241 3.00e7 4.20e11 2024-09-01 09:39:27 <ps_handl>
## 5 80366 1 mdwo… gaborcs… runni… 0.287 0.0797 3.00e7 4.20e11 2024-09-01 09:37:07 <ps_handl>
## 6 80360 69319 Goog… gaborcs… runni… 0.0462 0.0191 9.14e7 1.66e12 2024-09-01 09:37:05 <ps_handl>
## 7 80264 1 coun… root runni… NA NA NA NA 2024-09-01 09:36:10 <ps_handl>
## 8 80261 1 mdwo… gaborcs… runni… 0.300 0.0755 3.00e7 4.20e11 2024-09-01 09:35:55 <ps_handl>
## 9 78900 69319 Goog… gaborcs… runni… 2.26 0.429 1.76e8 1.66e12 2024-09-01 09:26:07 <ps_handl>
## 10 78888 69319 Goog… gaborcs… runni… 5.68 0.595 2.38e8 1.66e12 2024-09-01 09:25:57 <ps_handl>
## # ℹ 467 more rows
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=56773, NAME=R, AT=2024-08-31 14:11:26.708347
ps_pid(p) returns the pid of the process.
ps_pid(p)## [1] 56773
ps_create_time() returns the creation time of the process (according
to the OS).
ps_create_time(p)## [1] "2024-08-31 14:11:26 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] 55975
ps_parent(p) returns a process handle to the parent process of p.
ps_parent(p)## <ps::ps_handle> PID=55975, NAME=zsh, AT=2024-08-29 15:04:35.020175
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/4.4-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/4.4-arm64/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".
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/ttys015"
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/4.4-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
## 33.87137 15.05281 NA NA
ps_memory_info(p) returns memory usage information. See the manual for
details.
ps_memory_info(p)## rss vms pfaults pageins
## 255983616 423297335296 2173700 742
ps_children(p) lists all child processes (potentially recursively) of
the current process.
ps_children(ps_parent(p))## [[1]]
## <ps::ps_handle> PID=56773, NAME=R, AT=2024-08-31 14:11:26.708347
##
## [[2]]
## <ps::ps_handle> PID=57966, NAME=zsh, AT=2024-08-29 15:04:37.802087
ps_num_fds(p) returns the number of open file descriptors (handles on
Windows):
ps_num_fds(p)## [1] 49
f <- file(tmp <- tempfile(), "w")
ps_num_fds(p)## [1] 50
close(f)
unlink(tmp)ps_open_files(p) lists all open files:
ps_open_files(p)## # A data frame: 3 × 2
## fd path
## <int> <chr>
## 1 0 /dev/ttys015
## 2 1 /dev/ttys015
## 3 2 /dev/ttys015
f <- file(tmp <- tempfile(), "w")
ps_open_files(p)## # A data frame: 4 × 2
## fd path
## <int> <chr>
## 1 0 /dev/ttys015
## 2 1 /dev/ttys015
## 3 2 /dev/ttys015
## 4 45 /private/var/folders/ph/fpcmzfd16rgbbk8mxvy9m2_h0000gn/T/RtmpFPtZXU/fileddc51cac4863
close(f)
unlink(tmp)
ps_open_files(p)## # A data frame: 3 × 2
## fd path
## <int> <chr>
## 1 0 /dev/ttys015
## 2 1 /dev/ttys015
## 3 2 /dev/ttys015
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=56773, NAME=R, AT=2024-08-31 14:11:26.708347
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=56773, NAME=R, AT=2024-08-31 14:11:26.708347
ps_wait(), from ps 1.8.0, implements a new way, efficient for waiting
on a list of processes, so this is now very easy:
px <- processx::process$new("sleep", "2")
p <- px$as_ps_handle()
ps_wait(p, 1000)## [1] FALSE
ps_wait(p)## [1] TRUE
Again, this is much simpler with ps_wait(), added in ps 1.8.0.
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 <- px1$as_ps_handle()
p2 <- px2$as_ps_handle()
p3 <- px3$as_ps_handle()
p4 <- px4$as_ps_handle()
ps_wait(list(p1, p2, p3, p4), timeout = 2000)## [1] FALSE FALSE TRUE TRUE
From ps 1.8.0, ps_kill() will first send SIGTERM signals on Unix,
and SIGKILL after a grace period, if needed.
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.
kill_proc_tree <- function(pid, 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, list(parent))
ps_kill(children, ...)
}
p1 <- processx::process$new("sleep", "10")
p2 <- processx::process$new("sleep", "10")
p3 <- processx::process$new("sleep", "10")
kill_proc_tree(Sys.getpid(), include_parent = FALSE)## [1] "terminated" "terminated" "terminated" "terminated" "terminated"
Process name ending with “sh”:
ps() %>%
filter(grepl("sh$", name))## # A data frame: 38 × 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 67374 1 Report… gaborcs… runni… 0.00899 0.0148 5.47e6 4.20e11 2024-09-01 03:02:35 <ps_handl>
## 2 44801 44603 zsh gaborcs… runni… 0.00261 0.00945 7.86e5 4.21e11 2024-08-31 09:42:36 <ps_handl>
## 3 44603 44602 zsh gaborcs… runni… 0.155 0.0547 9.99e5 4.21e11 2024-08-31 09:42:35 <ps_handl>
## 4 24830 24631 zsh gaborcs… runni… 0.00736 0.0332 7.86e5 4.21e11 2024-08-30 22:11:24 <ps_handl>
## 5 24631 24630 zsh gaborcs… runni… 0.333 0.134 9.67e5 4.21e11 2024-08-30 22:11:24 <ps_handl>
## 6 58680 55972 zsh gaborcs… runni… 0.168 0.651 9.34e5 4.21e11 2024-08-29 15:04:39 <ps_handl>
## 7 58570 55971 zsh gaborcs… runni… 0.0186 0.0693 2.38e6 4.21e11 2024-08-29 15:04:39 <ps_handl>
## 8 58509 55974 zsh gaborcs… runni… 0.00364 0.0117 7.54e5 4.21e11 2024-08-29 15:04:38 <ps_handl>
## 9 58474 55964 zsh gaborcs… runni… 0.00367 0.00942 7.54e5 4.21e11 2024-08-29 15:04:38 <ps_handl>
## 10 58437 55966 zsh gaborcs… runni… 0.00341 0.00986 7.54e5 4.21e11 2024-08-29 15:04:38 <ps_handl>
## # ℹ 28 more rows
Processes owned by user:
ps() %>%
filter(username == Sys.info()[["user"]]) %>%
select(pid, name)## # A data frame: 286 × 2
## pid name
## <int> <chr>
## 1 81199 Google Chrome Helper (Renderer)
## 2 81198 Google Chrome Helper (Renderer)
## 3 81197 Google Chrome Helper (Renderer)
## 4 81068 mdworker_shared
## 5 81067 mdworker_shared
## 6 80413 mdworker_shared
## 7 80412 mdworker_shared
## 8 80366 mdworker_shared
## 9 80360 Google Chrome Helper (Renderer)
## 10 80261 mdworker_shared
## # ℹ 276 more rows
Processes consuming more than 100MB of memory:
ps() %>%
filter(rss > 100 * 1024 * 1024)## # A data frame: 29 × 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 81199 69319 Google… gaborcs… runni… 0.0412 0.0162 1.07e8 1.66e12 2024-09-01 09:39:54 <ps_handl>
## 2 81198 69319 Google… gaborcs… runni… 0.0704 0.0242 1.22e8 1.66e12 2024-09-01 09:39:53 <ps_handl>
## 3 81197 69319 Google… gaborcs… runni… 1.23 0.565 3.12e8 1.66e12 2024-09-01 09:39:53 <ps_handl>
## 4 78900 69319 Google… gaborcs… runni… 2.27 0.430 1.76e8 1.66e12 2024-09-01 09:26:07 <ps_handl>
## 5 78888 69319 Google… gaborcs… runni… 5.68 0.596 2.38e8 1.66e12 2024-09-01 09:25:57 <ps_handl>
## 6 76222 69319 Google… gaborcs… runni… 34.6 2.86 2.22e8 1.66e12 2024-09-01 09:17:46 <ps_handl>
## 7 74007 69319 Google… gaborcs… runni… 6.59 1.08 1.46e8 1.66e12 2024-09-01 08:37:02 <ps_handl>
## 8 73963 69319 Google… gaborcs… runni… 7.16 0.987 1.86e8 1.66e12 2024-09-01 08:34:37 <ps_handl>
## 9 73601 69319 Google… gaborcs… runni… 98.1 19.2 1.94e8 1.66e12 2024-09-01 07:54:27 <ps_handl>
## 10 69386 69319 Google… gaborcs… runni… 1.38 0.244 1.09e8 1.66e12 2024-09-01 07:06:19 <ps_handl>
## # ℹ 19 more rows
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 64110 1 com.apple… gaborcs… runni… 68283. 7992. 7.39e8 4.29e11 2024-07-17 08:14:51 <ps_handl>
## 2 56754 56683 ark gaborcs… runni… 813. 112. 5.66e8 4.22e11 2024-08-29 15:04:36 <ps_handl>
## 3 69319 1 Google Ch… gaborcs… runni… 280. 86.9 5.63e8 4.56e11 2024-09-01 07:06:06 <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 64110 com.apple.Virtualization.VirtualMachine 76275.
## 2 3525 Dato 12825.
## 3 2617 CursorUIViewService 6700.
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.
MIT © RStudio