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.\"
.\" mono manual page.
.\" Copyright 2003 Ximian, Inc.
.\" Copyright 2004-2009 Novell, Inc.
.\" Author:
.\" Miguel de Icaza (miguel@gnu.org)
.\"
.TH Mono "Mono 2.5"
.SH NAME
mono \- Mono's ECMA-CLI native code generator (Just-in-Time and Ahead-of-Time)
.SH SYNOPSIS
.PP
.B mono [options] file [arguments...]
.SH DESCRIPTION
\fImono\fP is a runtime implementation of the ECMA Common Language
Infrastructure. This can be used to run ECMA and .NET applications.
.PP
The runtime contains a native code generator that transforms the
Common Intermediate Language into native code.
.PP
The code generator can operate in two modes: just in time compilation
(JIT) or ahead of time compilation (AOT). Since code can be
dynamically loaded, the runtime environment and the JIT are always
present, even if code is compiled ahead of time.
.PP
The runtime loads the specified
.I file
and optionally passes
the
.I arguments
to it. The
.I file
is an ECMA assembly. They typically have a .exe or .dll extension.
.PP
The runtime provides a number of configuration options for running
applications, for developing and debugging, and for testing and
debugging the runtime itself.
.SH PORTABILITY
On Unix-based systems, Mono provides a mechanism to emulate the
Windows-style file access, this includes providing a case insensitive
view of the file system, directory separator mapping (from \\ to /) and
stripping the drive letters.
.PP
This functionality is enabled by setting the
.B MONO_IOMAP
environment variable to one of
.B all, drive
and
.B case.
.PP
See the description for
.B MONO_IOMAP
in the environment variables section for more details.
.SH RUNTIME OPTIONS
The following options are available:
.TP
\fB--aot\fR, \fB--aot[=options]\fR
This option is used to precompile the CIL code in the specified
assembly to native code. The generated code is stored in a file with
the extension .so. This file will be automatically picked up by the
runtime when the assembly is executed.
.Sp
Ahead-of-Time compilation is most useful if you use it in combination
with the -O=all,-shared flag which enables all of the optimizations in
the code generator to be performed. Some of those optimizations are
not practical for Just-in-Time compilation since they might be very
time consuming.
.Sp
Unlike the .NET Framework, Ahead-of-Time compilation will not generate
domain independent code: it generates the same code that the
Just-in-Time compiler would produce. Since most applications use a
single domain, this is fine. If you want to optimize the generated
code for use in multi-domain applications, consider using the
-O=shared flag.
.Sp
This pre-compiles the methods, but the original assembly is still
required to execute as this one contains the metadata and exception
information which is not available on the generated file. When
precompiling code, you might want to compile with all optimizations
(-O=all). Pre-compiled code is position independent code.
.Sp
Pre compilation is just a mechanism to reduce startup time, increase
code sharing across multiple mono processes and avoid just-in-time
compilation program startup costs. The original assembly must still
be present, as the metadata is contained there.
.Sp
AOT code typically can not be moved from one computer to another
(CPU-specific optimizations that are detected at runtime) so you
should not try to move the pre-generated assemblies or package the
pre-generated assemblies for deployment.
.Sp
A few options are available as a parameter to the
.B --aot
command line option. The options are separated by commas, and more
than one can be specified:
.RS
.ne 8
.TP
.I bind-to-runtime-version
.Sp
If specified, forces the generated AOT files to be bound to the
runtime version of the compiling Mono. This will prevent the AOT
files from being consumed by a different Mono runtime.
.I full
This is currently an experimental feature as it is not complete.
This instructs Mono to precompile code that has historically not been
precompiled with AOT.
.TP
.I write-symbols
Instructs the AOT compiler to emit debug symbol information.
.TP
.I static
Create an ELF object file (.o) which can be statically linked into an executable
when embedding the mono runtime. When this option is used, the object file needs to
be registered with the embedded runtime using the mono_aot_register_module function
which takes as its argument the mono_aot_module_<ASSEMBLY NAME>_info global symbol
from the object file:
.nf
extern void *mono_aot_module_hello_info;
mono_aot_register_module (mono_aot_module_hello_info);
.fi
.ne
.PP
For more information about AOT, see: http://www.mono-project.com/AOT
.RE
.TP
\fB--attach=[options]\fR
Currently the only option supported by this command line argument is
\fBdisable\fR which disables the attach functionality.
.TP
\fB--full-aot\fR
This is an experimental flag that instructs the Mono runtime to not
generate any code at runtime and depend exclusively on the code
generated from using mono --aot=full previously. This is useful for
platforms that do not permit dynamic code generation.
.Sp
Notice that this feature will abort execution at runtime if a codepath
in your program, or Mono's class libraries attempts to generate code
dynamically. You should test your software upfront and make sure that
you do not use any dynamic features.
.TP
\fB--config filename\fR
Load the specified configuration file instead of the default one(s).
The default files are /etc/mono/config and ~/.mono/config or the file
specified in the MONO_CONFIG environment variable, if set. See the
mono-config(5) man page for details on the format of this file.
.TP
\fB--desktop\fR
Configures the virtual machine to be better suited for desktop
applications. Currently this sets the GC system to avoid expanding
the heap as much as possible at the expense of slowing down garbage
collection a bit.
.TP
\fB--help\fR, \fB-h\fR
Displays usage instructions.
.TP
\fB--optimize=MODE\fR, \fB-O=MODE\fR
MODE is a comma separated list of optimizations. They also allow
optimizations to be turned off by prefixing the optimization name with
a minus sign.
.Sp
In general, Mono has been tuned to use the default set of flags,
before using these flags for a deployment setting, you might want to
actually measure the benefits of using them.
.Sp
The following optimizations are implemented:
.nf
all Turn on all optimizations
peephole Peephole postpass
branch Branch optimizations
inline Inline method calls
cfold Constant folding
consprop Constant propagation
copyprop Copy propagation
deadce Dead code elimination
linears Linear scan global reg allocation
cmov Conditional moves [arch-dependency]
shared Emit per-domain code
sched Instruction scheduling
intrins Intrinsic method implementations
tailc Tail recursion and tail calls
loop Loop related optimizations
fcmov Fast x86 FP compares [arch-dependency]
leaf Leaf procedures optimizations
aot Usage of Ahead Of Time compiled code
precomp Precompile all methods before executing Main
abcrem Array bound checks removal
ssapre SSA based Partial Redundancy Elimination
sse2 SSE2 instructions on x86 [arch-dependency]
gshared Enable generic code sharing.
.fi
.Sp
For example, to enable all the optimization but dead code
elimination and inlining, you can use:
.nf
-O=all,-deadce,-inline
.fi
.Sp
The flags that are flagged with [arch-dependency] indicate that the
given option if used in combination with Ahead of Time compilation
(--aot flag) would produce pre-compiled code that will depend on the
current CPU and might not be safely moved to another computer.
.TP
\fB--runtime=VERSION\fR
Mono supports different runtime versions. The version used depends on the program
that is being run or on its configuration file (named program.exe.config). This option
can be used to override such autodetection, by forcing a different runtime version
to be used. Note that this should only be used to select a later compatible runtime
version than the one the program was compiled against. A typical usage is for
running a 1.1 program on a 2.0 version:
.nf
mono --runtime=v2.0.50727 program.exe
.fi
.TP
\fB--security\fR, \fB--security=mode\fR
Activate the security manager, a currently experimental feature in
Mono and it is OFF by default. The new code verifier can be enabled
with this option as well.
.RS
.ne 8
.PP
Using security without parameters is equivalent as calling it with the
"cas" parameter.
.PP
The following modes are supported:
.TP
.I cas
This allows mono to support declarative security attributes,
e.g. execution of Code Access Security (CAS) or non-CAS demands.
.TP
.I core-clr
Enables the core-clr security system, typically used for
Moonlight/Silverlight applications. It provides a much simpler
security system than CAS, see http://www.mono-project.com/Moonlight
for more details and links to the descriptions of this new system.
.TP
.I validil
Enables the new verifier and performs basic verification for code
validity. In this mode, unsafe code and P/Invoke are allowed. This
mode provides a better safety guarantee but it is still possible
for managed code to crash Mono.
.TP
.I verifiable
Enables the new verifier and performs full verification of the code
being executed. It only allows verifiable code to be executed.
Unsafe code is not allowed but P/Invoke is. This mode should
not allow managed code to crash mono. The verification is not as
strict as ECMA 335 standard in order to stay compatible with the MS
runtime.
.PP
The security system acts on user code: code contained in mscorlib or
the global assembly cache is always trusted.
.ne
.RE
.TP
\fB--server\fR
Configures the virtual machine to be better suited for server
operations (currently, a no-op).
.TP
\fB--verify-all\fR
Verifies mscorlib and assemblies in the global
assembly cache for valid IL, and all user code for IL
verifiability.
This is different from \fB--security\fR's verifiable
or validil in that these options only check user code and skip
mscorlib and assemblies located on the global assembly cache.
.TP
\fB-V\fR, \fB--version\fR
Prints JIT version information (system configuration, release number
and branch names if available).
.SH DEVELOPMENT OPTIONS
The following options are used to help when developing a JITed application.
.TP
\fB--debug\fR, \fB--debug=OPTIONS\fR
Turns on the debugging mode in the runtime. If an assembly was
compiled with debugging information, it will produce line number
information for stack traces.
.RS
.ne 8
.PP
The optional OPTIONS argument is a comma separated list of debugging
options. These options are turned off by default since they generate
much larger and slower code at runtime.
.TP
The following options are supported:
.TP
.I casts
Produces a detailed error when throwing a InvalidCastException. This
option needs to be enabled as this generates more verbose code at
execution time.
.TP
.I mdb-optimizations
Disable some JIT optimizations which are usually only disabled when
running inside the debugger. This can be helpful if you want to attach
to the running process with mdb.
.TP
.I gdb
Generate and register debugging information with gdb. This is only supported on some
platforms, and only when using gdb 7.0 or later.
.ne
.RE
.TP
\fB--profile[=profiler[:profiler_args]]\fR
Turns on profiling. For more information about profiling applications
and code coverage see the sections "PROFILING" and "CODE COVERAGE"
below.
.TP
\fB--trace[=expression]\fR
Shows method names as they are invoked. By default all methods are
traced.
.Sp
The trace can be customized to include or exclude methods, classes or
assemblies. A trace expression is a comma separated list of targets,
each target can be prefixed with a minus sign to turn off a particular
target. The words `program', `all' and `disabled' have special
meaning. `program' refers to the main program being executed, and
`all' means all the method calls.
.Sp
The `disabled' option is used to start up with tracing disabled. It
can be enabled at a later point in time in the program by sending the
SIGUSR2 signal to the runtime.
.Sp
Assemblies are specified by their name, for example, to trace all
calls in the System assembly, use:
.nf
mono --trace=System app.exe
.fi
Classes are specified with the T: prefix. For example, to trace all
calls to the System.String class, use:
.nf
mono --trace=T:System.String app.exe
.fi
And individual methods are referenced with the M: prefix, and the
standard method notation:
.nf
mono --trace=M:System.Console:WriteLine app.exe
.fi
As previously noted, various rules can be specified at once:
.nf
mono --trace=T:System.String,T:System.Random app.exe
.fi
You can exclude pieces, the next example traces calls to
System.String except for the System.String:Concat method.
.nf
mono --trace=T:System.String,-M:System.String:Concat
.fi
Finally, namespaces can be specified using the N: prefix:
.nf
mono --trace=N:System.Xml
.fi
.TP
\fB--no-x86-stack-align\fR
Don't align stack frames on the x86 architecture. By default, Mono
aligns stack frames to 16 bytes on x86, so that local floating point
and SIMD variables can be properly aligned. This option turns off the
alignment, which usually saves one intruction per call, but might
result in significantly lower floating point and SIMD performance.
.SH JIT MAINTAINER OPTIONS
The maintainer options are only used by those developing the runtime
itself, and not typically of interest to runtime users or developers.
.TP
\fB--break method\fR
Inserts a breakpoint before the method whose name is `method'
(namespace.class:methodname). Use `Main' as method name to insert a
breakpoint on the application's main method.
.TP
\fB--breakonex\fR
Inserts a breakpoint on exceptions. This allows you to debug your
application with a native debugger when an exception is thrown.
.TP
\fB--compile name\fR
This compiles a method (namespace.name:methodname), this is used for
testing the compiler performance or to examine the output of the code
generator.
.TP
\fB--compileall\fR
Compiles all the methods in an assembly. This is used to test the
compiler performance or to examine the output of the code generator
.TP
\fB--graph=TYPE METHOD\fR
This generates a postscript file with a graph with the details about
the specified method (namespace.name:methodname). This requires `dot'
and ghostview to be installed (it expects Ghostview to be called
"gv").
.Sp
The following graphs are available:
.nf
cfg Control Flow Graph (CFG)
dtree Dominator Tree
code CFG showing code
ssa CFG showing code after SSA translation
optcode CFG showing code after IR optimizations
.fi
.Sp
Some graphs will only be available if certain optimizations are turned
on.
.TP
\fB--ncompile\fR
Instruct the runtime on the number of times that the method specified
by --compile (or all the methods if --compileall is used) to be
compiled. This is used for testing the code generator performance.
.TP
\fB--stats\fR
Displays information about the work done by the runtime during the
execution of an application.
.TP
\fB--wapi=hps|semdel\fR
Perform maintenance of the process shared data.
.Sp
semdel will delete the global semaphore.
.Sp
hps will list the currently used handles.
.TP
\fB-v\fR, \fB--verbose\fR
Increases the verbosity level, each time it is listed, increases the
verbosity level to include more information (including, for example,
a disassembly of the native code produced, code selector info etc.).
.SH ATTACH SUPPORT
The Mono runtime allows external processes to attach to a running
process and load assemblies into the running program. To attach to
the process, a special protocol is implemented in the Mono.Management
assembly.
.PP
With this support it is possible to load assemblies that have an entry
point (they are created with -target:exe or -target:winexe) to be
loaded and executed in the Mono process.
.PP
The code is loaded into the root domain, and it starts execution on
the special runtime attach thread. The attached program should
create its own threads and return after invocation.
.PP
This support allows for example debugging applications by having the
csharp shell attach to running processes.
.SH PROFILING
The mono runtime includes a profiler that can be used to explore
various performance related problems in your application. The
profiler is activated by passing the --profile command line argument
to the Mono runtime, the format is:
.nf
--profile[=profiler[:profiler_args]]
.fi
Mono has a built-in profiler called 'default' (and is also the default
if no arguments are specified), but developers can write custom
profilers, see the section "CUSTOM PROFILERS" for more details.
.PP
If a
.I profiler
is not specified, the default profiler is used.
.Sp
The
.I profiler_args
is a profiler-specific string of options for the profiler itself.
.Sp
The default profiler accepts the following options 'alloc' to profile
memory consumption by the application; 'time' to profile the time
spent on each routine; 'jit' to collect time spent JIT-compiling methods
and 'stat' to perform sample statistical profiling.
If no options are provided the default is 'alloc,time,jit'.
.PP
By default the
profile data is printed to stdout: to change this, use the 'file=filename'
option to output the data to filename.
.Sp
For example:
.nf
mono --profile program.exe
.fi
.Sp
That will run the program with the default profiler and will do time
and allocation profiling.
.Sp
.nf
mono --profile=default:stat,alloc,file=prof.out program.exe
.fi
Will do sample statistical profiling and allocation profiling on
program.exe. The profile data is put in prof.out.
.Sp
Note that the statistical profiler has a very low overhead and should
be the preferred profiler to use (for better output use the full path
to the mono binary when running and make sure you have installed the
addr2line utility that comes from the binutils package).
.SH LOGGING PROFILER
.PP
The
.I logging profiler
is a general purpose profiler that can track many different kinds of
events and logs those into a file as the program executes. This is
different than previous profilers in Mono that kept the information in
memory and rendered a summary of the results when the program shut
down.
.PP
Using the logging profiler means that useful information can be
gathered for long-running applications, applications that terminate
abormally (crashes, segfaults, complicated tear down processes) or
when no data about the shutdown is required.
.PP
The data collected by the running threads is kept independent of each
other to minimize the runtime overhead and the information dumped into
the log at regular intervals.
.PP
A sample use is very simple:
.nf
$ mono --profile=logging program.exe
$ mprof-decoder program.mprof
.fi
.PP
In the above example the logging profiler is used in its default mode
that merely records GC statistics for the execution of program.exe.
The profiling data collected is stored in the file program.mprof. The
mprof-decoder tool is then used to analyze the data.
.PP
You can instruct the logging profiler to record different one or more
sets of events. These are the modes supported:
.IP
.I Statistical Profiling (stat)
the program instruction pointer is periodically sampled to determine
where the program is spending most of its time. Statistical
profiling has a very low impact on a running application and it is
very useful to get a general picture of where time is being spent on a
program.
.IP
If call chains are requested, for each sample the profiler gets a
partial stack trace (limited by the specified depth) so that
caller-callee information is available.
.IP
.I Instrumenting:
each method enter and exit is logged with a timestamp; further processing of
the data can show the methods that took the longer to execute, with complete
accounting for callers and callees. However, this way of profiling is rather
intrusive and slows down the application significantly.
.IP
.I Allocation:
each allocation is logged.
.IP
.I Allocation summary:
shows, for each collection, a summary of the heap contents broken down by
class (for each class the number of allocated and released objects is
given, together with their aggregated size in bytes).
.IP
.I Heap snapshot mode:
dumps the whole heap contents at every collection (or at user specified
collections). It is also possible to request a collection and snapshot dump
with a signal.
.PP
Moreover, other events can be logged and analyzed, like jit time for each
method, load and unload for assemblies, modules and and individual classes,
and appdomain and thread creation and destruction.
.PP
This profiler is activated passing the \fB--profile=logging\fR option to
the mono runtime, and is controlled attaching further options, like
\fB--profile=logging:statistical\fR for doing statistical profiling (multiple
options are separated by commas).
.PP
As a quick primer, here are a few examples of the most common usage modes:
.PP
To perform statistical profiling:
.nf
mono --profile=logging:stat program.exe
.fi
.PP
To perform statistical profiling, inspecting call chains up to depth 8:
.nf
mono --profile=logging:stat=8 program.exe
.fi
.PP
To profile allocations (by default the call stack will be analized for
each allocation, producing detailed caller method attribution infornation):
.nf
mono --profile=logging:allocations program.exe
.fi
.PP
To profile garbage collection activity at a high level (collection time and objects freed
at each collection for each class are reported, but heap snapshots are not saved to disk):
.nf
mono --profile=logging:allocations-summary program.exe
.fi
.PP
To perform heap profiling taking heap snapshots:
.nf
mono --profile=logging:heap=all program.exe
.fi
.PP
To write the resulting data to a different file:
.nf
mono --profile=logging:output=mydata.mprof program.exe
.fi
.PP
Then you would need to invoke the decoder \fImprof-decoder(1)\fR
on the output file to see the profiling results, or to examine heap
snapshots and allocations in detail \fImprof-heap-viewer(1)\fR.
.PP
The operating modes described above are the default ones, and are sufficient
to use the profiler.
.PP
To further customize the profiler behavior there are more options, described
below.
.PP
These options can be individually enabled and disabled prefixing them
with an (optional) '+' character or a '-' character. For instance,
the "allocations" option by default records also the full call stack
at each allocation. If only the caller is wanted, one should use
"allocations,-save-allocation-stack", or to disable call tracking
completely (making the profiler less intrusive)
"allocations,-save-allocation-caller,-save-allocation-stack". In
practice the "allocation" option by default behaves like
"allocations,save-allocation-caller,save-allocation-stack", but the
user can tune this to his needs.
.PP
These are all the available options, organized by category:
.PP
\fBExecution profiling modes\fR
.RS
.ne 8
.TP
\fIstatistical\fR, \fIstat\fR or \fIs\fR
Performs statistical profiling. This is a lightweight profiling
mechanism and it has a much lower overhead than the \fIenter-leave\fR
profiling as it works by sampling where the program is spending its
time by using a timer.
If specified with \fIs=<number>\fR, also inspect call chains up to level
<number>.
.TP
\fIenter-leave\fR, \fIcalls\fR or \fIc\fR
Measure the time spent inside each method call, this is done by
logging the time when a method enters and when the method leaves.
This can be a time consuming operation.
.TP
\fIjit\fR, \fIj\fR
Collect information about time spent by the JIT engine compiling
methods.
.ne
.RE
.PP
\fBAllocation profiling modes\fR
.RS
.ne 8
.TP
\fIallocations\fR, \fIalloc\fR or \fIa\fR
Collect information about each allocation (object class and size).
By default this also implies "+save-allocation-caller" and
"+save-allocation-stack".
.TP
\fIsave-allocation-caller\fR, \fIsac\fR
Save the direct caller of each allocation. The profiler filters out wrapper
methods, and also recognizes if the allocation has been performed by the
runtime while jitting a method.
.TP
\fIsave-allocation-stack\fR, \fIsas\fR
Save the full managed execution stack at each allocation.
While the "sac" option saves the direct caller, this one records the whole
stack trace.
Note that in the call stack the wrapper methods are not filtered out.
Anyway the "sac" and "sas" options can be combined, and the decoder will
attribute the allocation to the correct method even if the wrapper is at the
top of the stack trace.
.TP
\fIallocations-summary\fR or \fIas\fR
At each collection dump a summary
of the heap contents (for each class, the number and collective size of all
live and freed heap objects). This very lightweight compared to full heap
snapshots.
.TP
\fIunreachable\fR, \fIfree\fR or \fIf\fR
Performs a lightweight profile of the garbage collector. On each
collection performed by the GC, the list of unreachable objects is
recorded, and for each object the class and size is provided. This
information can be used to compute the heap size broken down by class
(combined with "a" can give the same information of "as", but the log
file contains info about each individual object, while in "as" the
processing is done directly at runtime and the log file contains only
the summarized data broken down by class).
.TP
\fIgc\fR or \fIg\fR
Measure the time spent in each collection, and also trace heap resizes.
.TP
\fIheap-shot[=ARG]\fR, \fIheap[=ARG]\fR or \fIh[=ARH]\fR
Performs full heap profiling. In this case on each
collection a full heap snapshot is recorded to disk.
Inside the snapshots, each object reference is still represented so
that it's possible to investigate who is responsible for keeping objects
alive.
.PP
If the value of ARG is
.B all,
a heap snapshot is taken at each collection.
.PP
If the value is an integer
.B n,
a snapshot will be taken at the first
.B n
collections (like setting
.B gcd=n
);
.PP
If no additional argument is given to the heap option, the only way to take
heap snapshots is to requeste them using the runtime socket based command
interface described below (see "Profiler activity control").
.PP
Heap profiling also enables full allocation profiling (with call
stacks), and each allocation can be related to its corresponding
object in the snapshots, enabling investigations like "find all
objects of a given class allocated by a given method and still live at
a given collection, and then find all objects referencing them".
.PP
This kind of heap snapshot analysis is performed using the mprof-heap-viewer(1)
application.
.PP
The number of heap snapshots taken (and the moment in which they are taken)
can be further customized with the following options:
.TP
\fIgc-dumps=N\fR, \fIgc-d=N\fR, \fIgcd=N\fR
states the number of snapshots that must be dumped (since the application
starts). Zero means no dumps at all, -1 means dump at all collections.
.TP
These options exist because it can happen that the user wants to investigate
what happens during collections but without forcing a collection using the
command interface, because forcing a collection alters the program behavior.
Of course it is possible to simply take a snapshot at every collection, but
in some workloads this is could not be feasible (too much data).
So we have this "garbage collection dumps" counter to control how many
snapshots to take.
.ne
.RE
.PP
\fBProfiler activity control\fR
.RS
.ne 8
.TP
\fIoutput=FILE\fR, \fIout=FILE\fR or \fIo=FILE\fR
Use this option to provide the output file name for the profile log.
If this option is not specified, it will default to "<program-name>.mprof".
.TP
\fIoutput-suffix=SUFFIX\fR, \fIsuffix=SUFFIX\fR or \fIos=SUFFIX\fR: makes
the output file name equals to "<program-name>-SUFFIX.mprof".
.TP
\fIstart-enabled\fR or \fIse\fR: start with the profiler active
(which is the default).
.TP
\fIstart-disabled\fR or \fIsd\fR: start with the profiler inactive.
.TP
\fIforce-accurate-timer\fR (or \fIfac\fR): the profiler by default uses
rtdsc to acquire timestamps for frequent events, but this can be imprecise;
using this option you force the use of "gettimeofday" at every event, which
is more accurate but much slower.
.TP
\fIcommand-port=port\fR or \fIcp=port\fR (where port is an integer between
1024 nd 65535):
Choose a TCP port where the profiler will listen for user commands.
The protocol is ASCII based and line oriented (one line per command), and the
profiler answers with one line containing either "OK" or "ERROR" to each
received command.
.PP
The user can telnet to this port and give commands manually, or a GUI can
use this facility to control the profiler at runtime.
.PP
The available commands are:
.TP
\fIenable\fR: Enables the profiler.
.TP
\fIdisable\fR: Disables the profiler.
.TP
\fIheap-snapshot\fR: Takes a heap snapshot now (forces a full garbage collection).
.TP
\fIheap-snapshot-counter=arg\fR: Set the counter of the next heap snapshots
that must be taken, where arg can be "all" (take a snapshot at every
collection), "none" (do not take snapshots), or an integer "n" (take a heap
snapshot for the next "n" collections).
.ne
.RE
.PP
\fBInternal buffer sizes\fR
.RS
.ne 8
.TP
\fIper-thread-buffer-size=N\fR, \fItbs=N\fR
Use to specify the number of events that a thread buffer
can hold. When the thread buffer is full, a log block is
written to disk.
.Sp
This defaults to tbs=10000.
.TP
\fIstatistical-thread-buffer-size=N\fR, \fIsbs=N\fR
The number of statistical samples that
are held in memory before they are dumped to disk (the system does
double-buffering and the statistical samples are written by a helper
thread, so the statistical profiler never stops and is able to profile
the profiler itself).
.Sp
This defaults to sbs=10000.
.TP
\fIwrite-buffer-size\fR, \fIwbs\fR
Specifies the size in bytes of the internal write buffers.
.Sp
This defaults to wbs=1024.
.ne
.RE
.PP
In its current state, this profiler can also perform heap analysis
like the HeapShot profiler, but there is no UI to process this
information.
.PP
Another known issue is that if the timer is not strictly monotonic (like
rtdsc), differences between times can underflow (they are handled as
unsigned integers) and weird numbers can show up in the logs.
.PP
Finally, it can happen that when exceptions are thrown the profiler temporarily
loses track of the execution stack and misattributes the caller for a few
allocations (and method execution time).
.PP
The output file contains compressed events, to process the data you should
use tools like the "Mono.Profiler" tool provided on the Mono SVN
repository.
.PP
More explanations are provided here: "http://www.mono-project.com/LoggingProfiler".
.SH EXTERNAL PROFILERS
There are a number of external profilers that have been developed for
Mono, we will update this section to contain the profilers.
.PP
The heap Shot profiler can track all live objects, and references to
these objects, and includes a GUI tool, this is our recommended
profiler.
To install you must download the profiler
from Mono's SVN:
.nf
svn co svn://anonsvn.mono-project.com/source/trunk/heap-shot
cd heap-shot
./autogen
make
make install
.fi
.PP
See the included documentation for details on using it.
.PP
The Live Type profiler shows at every GC iteration all of the live
objects of a given type. To install you must download the profiler
from Mono's SVN:
.nf
svn co svn://anonsvn.mono-project.com/source/trunk/heap-prof
cd heap-prof
./autogen
make
make install
.fi
.PP
To use the profiler, execute:
.nf
mono --profile=desc-heap program.exe
.fi
.PP
The output of this profiler looks like this:
.nf
Checkpoint at 102 for heap-resize
System.MonoType : 708
System.Threading.Thread : 352
System.String : 3230
System.String[] : 104
Gnome.ModuleInfo : 112
System.Object[] : 160
System.Collections.Hashtable : 96
System.Int32[] : 212
System.Collections.Hashtable+Slot[] : 296
System.Globalization.CultureInfo : 108
System.Globalization.NumberFormatInfo : 144
.fi
.PP
The first line describes the iteration number for the GC, in this case
checkpoint 102.
.PP
Then on each line the type is displayed as well as the number of bytes
that are being consumed by live instances of this object.
.PP
The AOT profiler is used to feed back information to the AOT compiler
about how to order code based on the access patterns for pages. To
use it, use:
.nf
mono --profile=aot program.exe
.fi
The output of this profile can be fed back into Mono's AOT compiler to
order the functions on the disk to produce precompiled images that
have methods in sequential pages.
.SH CUSTOM PROFILERS
Mono provides a mechanism for loading other profiling modules which in
the form of shared libraries. These profiling modules can hook up to
various parts of the Mono runtime to gather information about the code
being executed.
.PP
To use a third party profiler you must pass the name of the profiler
to Mono, like this:
.nf
mono --profile=custom program.exe
.fi
.PP
In the above sample Mono will load the user defined profiler from the
shared library `mono-profiler-custom.so'. This profiler module must
be on your dynamic linker library path.
.PP
A list of other third party profilers is available from Mono's web
site (www.mono-project.com/Performance_Tips)
.PP
Custom profiles are written as shared libraries. The shared library
must be called `mono-profiler-NAME.so' where `NAME' is the name of
your profiler.
.PP
For a sample of how to write your own custom profiler look in the
Mono source tree for in the samples/profiler.c.
.SH CODE COVERAGE
Mono ships with a code coverage module. This module is activated by
using the Mono --profile=cov option. The format is:
\fB--profile=cov[:assembly-name[/namespace]] test-suite.exe\fR
.PP
By default code coverage will default to all the assemblies loaded,
you can limit this by specifying the assembly name, for example to
perform code coverage in the routines of your program use, for example
the following command line limits the code coverage to routines in the
"demo" assembly:
.nf
mono --profile=cov:demo demo.exe
.fi
.PP
Notice that the
.I assembly-name
does not include the extension.
.PP
You can further restrict the code coverage output by specifying a
namespace:
.nf
mono --profile=cov:demo/My.Utilities demo.exe
.fi
.PP
Which will only perform code coverage in the given assembly and
namespace.
.PP
Typical output looks like this:
.nf
Not covered: Class:.ctor ()
Not covered: Class:A ()
Not covered: Driver:.ctor ()
Not covered: Driver:method ()
Partial coverage: Driver:Main ()
offset 0x000a
.fi
.PP
The offsets displayed are IL offsets.
.PP
A more powerful coverage tool is available in the module `monocov'.
See the monocov(1) man page for details.
.SH DEBUGGING AIDS
To debug managed applications, you can use the
.B mdb
command, a command line debugger.
.PP
It is possible to obtain a stack trace of all the active threads in
Mono by sending the QUIT signal to Mono, you can do this from the
command line, like this:
.nf
kill -QUIT pid
.fi
Where pid is the Process ID of the Mono process you want to examine.
The process will continue running afterwards, but its state is not