SHARK4(1)						    BSD General Commands Manual 						 SHARK4(1)

NAME

     shark -- creates *.mshark profiles of system or process behavior for viewing with Shark.app.

SYNOPSIS

     shark [-1] [-a process] [-b] [-c index] [-d path] [-e] [-f file] [-G] [-g] [-i] [-I interval] [-l] [-L] [-m file] [-N] [-o basename] [-q]
	   [-r] [-S limit] [-t] [-T limit] [-u] [-v] [-x] [executable [args...]]

DESCRIPTION

     shark helps you tune and understand your code for optimal performance.  At the simplest level, shark profiles the system to see how time is
     being spent. It can also produce profiles of hardware and software performance events such as cache misses, virtual memory activity, instruc-
     tion dependency stalls, system traces, and other types of profiles.  Using these profiles, you can focus your optimization efforts on perfor-
     mance-critical code.

     shark creates a profile of execution behavior by periodically interrupting each processor in the system and sampling the currently running
     process, thread and instruction address. Along with this contextual information, shark records the values of the available hardware and soft-
     ware performance counters.  Each performance counter is capable of counting a wide variety of performance events. In the case of processor
     and memory controller counters, these include detailed, low-level information that is otherwise impossible to know without a simulator.

     The profiles generated by shark are statistical in nature; they give a representative view of what was running on the system during a sam-
     pling session. Samples can include all of the processes running on the system from both user and supervisor code.

     Sampling is controlled by:

     Immediately (-i option) - sampling begins immediately and ends when either the current max sample limit is reached or the launched/attached
     target process exits

     Hotkey - option-esc to start/stop sampling, ctrl-esc to quit (available only to the currently logged in user)

     Remote - (-r option) - There are several ways to toggle profiling when shark is in 'remote' mode. 1: A CHUD remote client program can be
     instrumented with calls to: chudStartRemotePerfMonitor()/chudStopRemotePerfMonitor() to start/stop sampling. 2: The utility chudRemoteCtrl(1)
     can be used on the command line of a terminal to start or stop the collection of performance monitor samples. 3: The UNIX signals SIGUSR1 and
     SIGUSR2 can be sent to shark via its process id (pid) number, to start or stop performance monitoring. Sending the SIGUSR1 signal toggles the
     start and stop of sampling.  Sending a SIGUSR2 stops sampling and causes a session file to be generated if need be.  When you are using shark
     over a remote shell (rlogin, telnet, ssh, etc.) connection, you will need to run shark and the chudRemoteCtrl(1) utility in the same session
     (remote shell). The UNIX signal method is the most reliable.  And it works from a separate shell logged into the same account as the shell
     running shark In fact the chudRemoteCtrl(1) utility can send the appropriate UNIX signals to shark from a separate shell. But the most direct
     way to send UNIX signals is by using the kill(1) utility:

	 for example: % kill -s USR1 <pid>

	 % chudRemoteCtrl -s <session_name> -k<pid>

	 will start sampling using SIGUSR1; and

	 % chudRemoteCtrl -e -k<pid>

	 will stop sampling using SIGUSR2, which also creates the session file (if any).

     Profiling over a remote shell works very well if you have shark launch an executable that has been instrumented with the CHUD functions. Typ-
     ical instrumentation might look like:

     //add the header file

     #include <CHUD/CHUD.h>

     //then in the main...

     chudInitialize();

     chudAcquireRemoteAccess();

     //just before the code to be profiled

     chudStartRemotePerfMonitor("some run label");

     //just after the code to be profiled

     chudStopRemotePerfMonitor();

     //before the program exits:

     chudReleaseRemoteAccess();

     Network Sharing (-N option) - a message is sent to the shark program, from another computer on the network, to toggle profiling. Typically,
     one system, on the network, is running Shark.app.	The Shark.app program will have been configured to manage other profiling "service" pro-
     grams.  shark is a profiling service program when the '-N' option is given on the command line.  In network sharing mode shark can still be
     triggered by signals and by hotkeys on the local host.  The sessions generated by shark will be cached and delivered to the controlling Shark
     application when the Shark application requests the session file, or as soon as it is available, if the Shark application requests automatic
     delivery of sessions from the profiling services. One shark program can be run on each of many systems on the network.  One system running
     Shark.app can control profiling on all of the systems running shark simultaneously.

OPTIONS

     -1 	 Sample only the target process (specified through -a process or the launched executable).

     -a process  Attach to a currently running process with the specified name or PID.	If a process is not given, shark can also optionally
		 launch a new process from a specified executable.  If neither -a process or an executable is specified, shark will wait for fur-
		 ther input (either a the start/stop hotkey, option-esc, or a CHUD remote monitoring start message if remote monitoring is
		 enabled).

     -b 	 Enable batch mode. By default, shark will exit after recording a single *.mshark session file.  This option allows you to record
		 multiple sessions without exiting shark.

     -c index	 Specifies the index of the sampling configuration to be used.

     -d path	 Sets the directory file path name used for *.mshark session files. By default this is not set to anything. So shark generates
		 session files in the current working directory. No directories are created by shark.  NOTE: If a directory path is set with this
		 option, then including a slash (/) as the first component of the basename argument (to the '-o' option, above) will generate a
		 fatal error.

     -e 	 List the current settings of search-path environment variables used by shark to locate various types of files during session pro-
		 cessing.  There are currently two environment variables: SHARK_SEARCH_PATH_KEXT_FILES and SHARK_SEARCH_PATH_SOURCE_FILES.  shark
		 will search the colon delimited lists of file paths for Kernel Extensions and Source Files, respectively.  NOTE: Even if no
		 search paths are specified for Kernel Extensions (SHARK_SEARCH_PATH_KEXT_FILES) some paths will be listed; shark adds to these
		 paths automatically.

     -f file	 Specifies the path to an executable, or (MachO) object file to be statically analyzed. This file is used in conjunction with a
		 shark -Static Analysis- config file. The config file must be specified with the '-c' or '-m' options.

     -G 	 Create a brief textual report from each analysis module that is active in the profiling config.  If an analysis module does not
		 support plain text reporting a "<NO REPORT AVAILABLE>" message is printed.  The text report will have the same name as the ses-
		 sion except the extension will be "...-report.txt" instead of ".mshark"

     -g session file name(s)
		 Create a brief textual report from any analysis modules that are active in each session file named on the command line.  If an
		 analysis module does not support plain text reporting a "<NO REPORT AVAILABLE>" message is put in the report.	The text report
		 will have the same name as the related session file except the extension will be "...-report.txt" instead of ".mshark"

     -i 	 Begin sampling immediately, exiting after a session has been taken.

     -I interval
		 Change the per-sample time interval to this value. Enter the value as a number followed by a suffix: for example 5m would set the
		 per-sample time interval to 5 milliseconds.  50u would change the per-sample time limit to 50 microseconds. 5s would change the
		 per-sample time limit to 5 seconds.

     -l 	 Lists the available sampling configurations and exits. New sampling configurations can be created with Shark.app (the GUI version
		 of shark ).  shark looks for user configurations in ~/Library/Application Support/Shark/Configs.

     -L 	 Similar to -l option, but adds detailed description of each configuration.

     -m file	 Specifies the path to a shark sampling config (*.cfg) file to be used.

     -N 	 Enables Network Sharing mode in the shark program. Enabling network sharing does not disable any of the other methods for start-
		 ing and stopping profiling.

     -o basename
		 Sets the basic file name used for *.mshark session files.  By default this is "session", which generates session files named ses-
		 sion_{x}.mshark in the current working directory. The 'basename' can contain relative path information, or absolute path informa-
		 tion if the '-d' option is not specified on the command line.	shark will honor the file path specified before the basename, pro-
		 vided ALL the directories in the path exist already. No directories are created by shark.

     -q 	 Quiet mode. Runs silently (no output to terminal) unless an error is encountered.

     -r 	 Enable remote monitoring mode. In this mode shark waits for a CHUD remote client program to call chudStartRemotePerfMoni-
		 tor()/chudStopRemotePerfMonitor() to start and stop sampling. (see above for more details on this option)

     -S limit	 Change the sample limit to this <limit> number of samples.

     -t [session file name(s)]
		 Create a text output file representing the complete analysis from the session for each analysis module active in the session.
		 Note that not every analysis module supports full-text output. If a module does not support full-text output, the phrase:

		 <FULL-TEXT FORMAT NOT AVAILABLE> appears in the text file for that module.  The full-text output file will have the same name as
		 the session except the extension will be "...-full.txt" instead of ".mshark".

		 Session file names are optional; if omitted, full text reports will be generated for each session you take.  If included, no ses-
		 sion will be taken - instead, text reports will be generated from the given session file names.

		 The '-t' option and the '-G' option can both be used at the same time, since they create different filenames.

     -T limit	 Change the maximum time limit to this value. Enter the value as a number followed by a suffix: for example 500m would set the
		 time limit to 500 milliseconds.  500000u would change the time limit to 500000 microseconds. 22s would change the sampling time
		 limit to 22 seconds.

     -u 	 Identify processes by name (the default behavior is to identify processes by PID).

     -v 	 Prints the Shark version and exits.

     -w 	 After stopping sampling, wait until the user presses Return before creating the session file.

     -x 	 Ignore task will exit notifications. Normally shark will be notified whenever a process (task) exits while it is sampling.  This
		 allows for all relevant symbol and other information required for later analysis to be gathered before allowing the exiting task
		 to complete exiting.  The processing that occurs during a task exit notification can cause gaps in the resulting profile.

BUGS

     Please send your comments, suggestions and bug reports to: perftools-feedback@group.apple.com

SEE ALSO

     chudRemoteCtrl(1), kill(1), /Developer/Documentation/CHUD/Shark/SharkUserGuide.pdf

								   May 31, 2019