Package 'autometric'

Check the log thread.

Description

Check if the log is running.

Usage

log_active()

Value

TRUE if a background thread is actively writing to the log, FALSE otherwise. The result is based on a static C variable, so the information is second-hand.

Examples

path <- tempfile()
  log_active()
  log_start(seconds = 0.5, path = path)
  log_active()
  Sys.sleep(2)
  log_stop()
  Sys.sleep(2)
  log_active()
  unlink(path)

---

Get log phase

Description

Get the current log phase.

Usage

log_phase_get()

Value

Character string with the name of the current log phase.

Examples

path <- tempfile()
  log_phase_get()
  log_print(path = path)
  log_phase_set("different")
  log_phase_get()
  log_print(path = path)
  log_phase_reset()
  log_phase_get()
  log_read(path)

---

Reset log phase

Description

Reset the current log phase to the default value.

Usage

log_phase_reset()

Value

NULL (invisibly). Called for its side effects.

Examples

path <- tempfile()
  log_phase_get()
  log_print(path = path)
  log_phase_set("different")
  log_phase_get()
  log_print(path = path)
  log_phase_reset()
  log_phase_get()
  log_read(path)

---

Set log phase

Description

Set the current log phase.

Usage

log_phase_set(phase)

Arguments

phase

Character string with the phase of the log. Only the first 255 characters are used. Cannot include the pipe character "|" because it is the delimiter of fields in the log output.

Value

NULL (invisibly). Called for its side effects.

Examples

path <- tempfile()
  log_phase_get()
  log_print(path = path)
  log_phase_set("different")
  log_phase_get()
  log_print(path = path)
  log_phase_reset()
  log_phase_get()
  log_read(path)

---

Plot a metric of a process over time

Description

Visualize a metric of a log over time for a single process ID in a single log file.

Usage

log_plot(log, pid = NULL, name = NULL, phase = NULL, metric = "resident", ...)

Arguments

log	Data frame returned by log_read(). Must be nonempty. log_plot() only includes rows with status code equal to 0.
pid	Either NULL or a non-negative integer with the process ID to plot. At least one of pid or name must be NULL.
name	Either NULL or a non-negative integer with the name of the process to plot. The name was previously specified in the names of the pid argument of log_start() or log_print(). At least one of pid or name must be NULL.
phase	Either NULL or a character string specifying the name of a log phase (see log_phase_set()). If not NULL, then log_print() will only visualize data from the given log phase.
metric	Character string with the name of a metric to plot against time. Must be only a single string. Defaults to the resident set size (RSS), the total amount of memory used by the process. See log_read() for descriptions of the metrics available.
...	Named optional parameters to pass to the base function plot().

Value

A base plot of a metric of a log over time.

Examples

path <- tempfile()
  log_start(seconds = 0.25, path = path)
  Sys.sleep(1)
  log_stop()
  Sys.sleep(2)
  log <- log_read(path)
  log_plot(log, metric = "cpu")
  unlink(path)

---

Print once to the log.

Description

Sample CPU load metrics and print a single line to the log for each process in pids. Used for debugging and testing only. Not for users.

Usage

log_print(
  path,
  seconds = 1,
  pids = c(local = Sys.getpid()),
  error = getOption("autometric_error", TRUE)
)

Arguments

path	Character string, path to a file to log resource usage. On Windows, the path must point to a physical file on disk. On Unix-like systems, path can be "/dev/stdout" to print to standard output or "/dev/stderr" to print to standard error. Standard output is the most convenient option for high-performance computing scenarios where worker processes already write to log files. Such workers usually already redirect standard output to a physical file, as with a cluster like SLURM, or capture messages with Amazon CloudWatch. Normally, standard output and standard error are discouraged because of how they interact with the R API and R console. However, the exported user interface of autometric only ever prints from a detached POSIX thread where it is unsafe to use Rprintf() or REprintf().
seconds	Positive number, number of seconds to sample CPU load metrics before printing to the log. This number should be at least 1, usually more. A low number of seconds could burden the operating system and generate large log files.
pids	Nonempty vector of non-negative integers of process IDs to monitor. NOTE: On Mac OS, only the currently running process can be monitored. This is due to security restrictions around certain system calls, c.f. https://os-tres.net/blog/2010/02/17/mac-os-x-and-task-for-pid-mach-call/. # nolint If the pids vector is named, then the names will show alongside the process IDs in the log entries. Names cannot include the pipe character "|" because it is the delimiter of fields in the log output.
error	TRUE to throw an error if the thread is not supported on the current platform. (See log_support().)

Value

NULL (invisibly). Called for its side effects.

Examples

path = tempfile()
  log_print(path = path)
  log_read(path)
  unlink(path)

---

Read a log.

Description

Read a log file into R.

Usage

log_read(
  path,
  units_cpu = c("percentage", "fraction"),
  units_memory = c("megabytes", "bytes", "kilobytes", "gigabytes"),
  units_time = c("seconds", "minutes", "hours", "days"),
  hidden = FALSE
)

Arguments

path	Character vector of paths to files and/or directories of logs to read.
units_cpu	Character string with the units of the cpu field. Defaults to "percentage" and must be in c("percentage", "fraction").
units_memory	Character string with the units of the memory field. Defaults to "megabytes" and must be in c("megabytes", "bytes", "kilobytes", "gigabytes").
units_time	Character string, units of the time field. Defaults to "seconds" and must be in c("seconds", "minutes", "hours", "days").
hidden	TRUE to include hidden files in the files and directories listed in path, FALSE to omit.

Details

log_read() is capable of reading a log file where both autometric and other processes have printed. Whenever autometric writes to a log, it bounds the beginning and end of the text with the keyword "__AUTOMETRIC__". that way, log_read() knows to only read and process the correct lines of the file.

In addition, it automatically converts the log data into the units units_time, units_cpu, and units_memory arguments.

Value

A data frame of metrics from the log with one row per log entry and columns with metadata and resource usage metrics. log_read() automatically converts the data into the units chosen with arguments units_time, units_cpu, and units_memory. The returned data frame has the following columns:

• version: Version of the package used to write the log entry.

• pid: Process ID monitored.

• status: A status code for the log entry. Status 0 means logging succeeded. A status code not equal to 0 indicates something went wrong and the metrics should not be trusted.

• time: numeric time stamp at which the entry was logged. log_read() automatically recenters this column so that time 0 indicates the first logged entry. Use the units_time argument to customize the units of this field.

• core: CPU load of the process scaled relative to a single CPU core. Measures the amount of time the process spends running during a given interval of elapsed time.

  On Mac OS, the package uses native system calls to get CPU core usage. On Linux and Windows, the package calculates it manually using. user + kernel clock cycles that ran during a sampling interval. It measures the clock cycles that the process executed during the interval, converts the clock cycles into seconds, then divides the result by the elapsed time of the interval. The length of the sampling interval is the seconds argument supplied to log_start(), or length of time between calls to log_print(). The first core measurement is 0 to reflect that a full sampling interval has not elapsed yet.

  core can be read in as a percentage or fraction, depending on the units_cpu argument.

• cpu: core divided by the number of logical CPU cores. This metric measures the load on the machine as a whole, not just the CPU core it runs on. Use the units_cpu argument to customize the units of this field.

• rss: resident set size, the total amount of memory used by the process at the time of logging. This include the memory unique to the process (unique set size USS) and shared memory. Use the units_memory argument to customize the units of this field.

• virtual: total virtual memory available to the process. The process does not necessarily use all this memory, but it can request more virtual memory throughout its life cycle. Use the units_memory argument to customize the units of this field.

Examples

path <- tempfile()
  log_start(seconds = 0.5, path = path)
  Sys.sleep(2)
  log_stop()
  Sys.sleep(2)
  log_read(path)
  unlink(path)

---

Start the log thread.

Description

Start a background thread that periodically writes system usage metrics of the current R process to a log file. See log_read() for explanations of the specific metrics.

Usage

log_start(
  path,
  seconds = 1,
  pids = c(local = Sys.getpid()),
  error = getOption("autometric_error", TRUE)
)

Arguments

path	Character string, path to a file to log resource usage. On Windows, the path must point to a physical file on disk. On Unix-like systems, path can be "/dev/stdout" to print to standard output or "/dev/stderr" to print to standard error. Standard output is the most convenient option for high-performance computing scenarios where worker processes already write to log files. Such workers usually already redirect standard output to a physical file, as with a cluster like SLURM, or capture messages with Amazon CloudWatch. Normally, standard output and standard error are discouraged because of how they interact with the R API and R console. However, the exported user interface of autometric only ever prints from a detached POSIX thread where it is unsafe to use Rprintf() or REprintf().
seconds	Positive number, number of seconds between writes to the log file. This number should be noticeably large, anywhere between half a second to several seconds or minutes. A low number of seconds could burden the operating system and generate large log files. Because of the way CPU usage measurements work, the first log entry starts only after after the first interval of seconds has passed.
pids	Nonempty vector of non-negative integers of process IDs to monitor. NOTE: On Mac OS, only the currently running process can be monitored. This is due to security restrictions around certain system calls, c.f. https://os-tres.net/blog/2010/02/17/mac-os-x-and-task-for-pid-mach-call/. # nolint If the pids vector is named, then the names will show alongside the process IDs in the log entries. Names cannot include the pipe character "|" because it is the delimiter of fields in the log output.
error	TRUE to throw an error if the thread is not supported on the current platform. (See log_support().)

Details

Only one thread can run at a time. If the thread is already running, then log_start() does not start an additional one. Before creating a new thread, call log_stop() to terminate the first one.

Value

NULL (invisibly). Called for its side effects.

Examples

path <- tempfile()
  log_start(seconds = 0.5, path = path)
  Sys.sleep(2)
  log_stop()
  Sys.sleep(2)
  log_read(path)
  unlink(path)

---

Stop the log thread.

Description

Stop the background thread that periodically writes system usage metrics of the current R process to a log file.

Usage

log_stop()

Details

The background thread is detached, so is there no way to directly terminate it (other than terminating the main thread, i.e. restarting R). log_stop() merely signals to the thread using a static C variable protected by a mutex. It may take time for the thread to notice, depending on the value of seconds you supplied to log_start(). For this reason, you may see one or two lines in the log even after you call log_stop().

Value

NULL (invisibly). Called for its side effects.

Examples

path <- tempfile()
  log_start(seconds = 0.5, path = path)
  Sys.sleep(2)
  log_stop()
  log_read(path)
  unlink(path)

---

Log support

Description

Check if your system supports background logging.

Usage

log_support()

Details

The background logging functionality requires a Linux, Mac, or Windows computer, It also requires POSIX thread support and the nanosleep() C function.

Value

TRUE if your system supports background logging, FALSE otherwise.

Examples

log_support()

---