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Branches: main Pack consecutive enumeration arguments in discriminated union types into a single word to reduce cell sizes. Argument packing is only enabled on C back-ends with low-level data, and reordering arguments to improve opportunities for packing is not yet attempted. The RTTI implementations for other back-ends will need to be updated, but that is best left until after any argument reordering change. Modules which import abstract enumeration types are notified so by writing declarations of the form: :- type foo where type_is_abstract_enum(NumBits). into the interface file for the module which defines the type. compiler/prog_data.m: Add an `arg_width' argument to constructor arguments. Replace `is_solver_type' by `abstract_type_details', with an extra option for abstract exported enumeration types. compiler/handle_options.m: compiler/options.m: Add an internal option `--allow-argument-packing'. compiler/make_hlds_passes.m: Determine whether and how to pack enumeration arguments, updating the `arg_width' fields of constructor arguments before constructors are added to the HLDS. compiler/mercury_to_mercury.m: compiler/modules.m: Write `where type_is_abstract_enum(NumBits)' to interface files for abstract exported enumeration types. compiler/prog_io_type_defn.m: Parse `where type_is_abstract_enum(NumBits)' attributes on type definitions. compiler/arg_pack.m: compiler/backend_libs.m: Add a new module. This mainly contains a predicate which packs rvals according to arg_widths, which is used by both LLDS and MLDS back-ends. compiler/ml_unify_gen.m: compiler/unify_gen.m: Take argument packing into account when generating code for constructions and deconstructions. Only a relatively small part of the compiler actually needs to understand argument packing. The rest works at the HLDS level with constructor arguments and variables, or at the LLDS and MLDS levels with structure fields. compiler/code_info.m: compiler/var_locn.m: Add assign_field_lval_expr_to_var and var_locn_assign_field_lval_expr_to_var. Allow more kinds of rvals in assign_cell_arg. I do not know why it was previously restricted, except that the other kinds of rvals were not encountered as cell arguments before. compiler/mlds.m: We can now rely on the compiler to pack arguments in the mlds_decl_flags type instead of doing it manually. A slight downside is that though the type is packed down to a single word cell, it will still incur a memory allocation per cell. However, I did not notice any difference in compiler speed. compiler/rtti.m: compiler/rtti_out.m: Add and output a new field for MR_DuFunctorDesc instances, which, if any arguments are packed, points to an array of MR_DuArgLocn. Each array element describes the offset in the cell at which the argument's value is held, and which bits of the word it occupies. In the more common case where no arguments are packed, the new field is simply null. compiler/rtti_to_mlds.m: Generate the new field to MR_DuFunctorDesc. compiler/structure_reuse.direct.choose_reuse.m: For now, prevent structure reuse reusing a dead cell which has a different constructor to the new cell. The code to determine whether a dead cell will hold the arguments of a new cell with a different constructor will need to be updated to account for argument packing. compiler/type_ctor_info.m: Bump RTTI version number. Conform to changes. compiler/add_type.m: compiler/check_typeclass.m: compiler/equiv_type.m: compiler/equiv_type_hlds.m: compiler/erl_rtti.m: compiler/hlds_data.m: compiler/hlds_out_module.m: compiler/intermod.m: compiler/make_tags.m: compiler/mlds_to_gcc.m: compiler/opt_debug.m: compiler/prog_type.m: compiler/recompilation.check.m: compiler/recompilation.version.m: compiler/special_pred.m: compiler/type_constraints.m: compiler/type_util.m: compiler/unify_proc.m: compiler/xml_documentation.m: Conform to changes. Reduce code duplication in classify_type_defn. compiler/hlds_goal.m: Clarify a comment. library/construct.m: Make `construct' pack arguments when necessary. Remove an old RTTI version number check as recommended in mercury_grade.h. library/store.m: Deal with packed arguments in this module. runtime/mercury_grade.h: Bump binary compatibility version number. runtime/mercury_type_info.c: runtime/mercury_type_info.h: Bump RTTI version number. Add MR_DuArgLocn structure definition. Add a macro to unpack an argument as described by MR_DuArgLocn. Add a function to determine a cell's size, since the number of arguments is no longer correct. runtime/mercury_deconstruct.c: runtime/mercury_deconstruct.h: runtime/mercury_deconstruct_macros.h: runtime/mercury_ml_arg_body.h: runtime/mercury_ml_expand_body.h: Deal with packed arguments when deconstructing. Remove an old RTTI version number check as recommended in mercury_grade.h. runtime/mercury_deep_copy_body.h: Deal with packed arguments when copying. runtime/mercury_table_type_body.h: Deal with packed arguments in tabling. runtime/mercury_dotnet.cs.in: Add DuArgLocn field to DuFunctorDesc. Argument packing is not enabled for the C# back-end yet so this is unused. trace/mercury_trace_vars.c: Deal with packed arguments in MR_select_specified_subterm, use for the `hold' command. java/runtime/DuArgLocn.java: java/runtime/DuFunctorDesc.java: Add DuArgLocn field to DuFunctorDesc. Argument packing is not enabled for the Java back-end yet so this is unused. extras/trailed_update/tr_store.m: Deal with packed arguments in this module (untested). extras/trailed_update/samples/interpreter.m: extras/trailed_update/tr_array.m: Conform to argument reordering in the array, map and other modules in previous changes. tests/hard_coded/Mercury.options: tests/hard_coded/Mmakefile: tests/hard_coded/lco_pack_args.exp: tests/hard_coded/lco_pack_args.m: tests/hard_coded/pack_args.exp: tests/hard_coded/pack_args.m: tests/hard_coded/pack_args_copy.exp: tests/hard_coded/pack_args_copy.m: tests/hard_coded/pack_args_intermod1.exp: tests/hard_coded/pack_args_intermod1.m: tests/hard_coded/pack_args_intermod2.m: tests/hard_coded/pack_args_reuse.exp: tests/hard_coded/pack_args_reuse.m: tests/hard_coded/store_ref.exp: tests/hard_coded/store_ref.m: tests/invalid/Mmakefile: tests/invalid/where_abstract_enum.err_exp: tests/invalid/where_abstract_enum.m: tests/tabling/Mmakefile: tests/tabling/pack_args_memo.exp: tests/tabling/pack_args_memo.m: Add new test cases. tests/hard_coded/deconstruct_arg.exp: tests/hard_coded/deconstruct_arg.exp2: tests/hard_coded/deconstruct_arg.m: Add constructors with packed arguments to these cases. tests/invalid/where_direct_arg.err_exp: Update expected output.
Threadscope
===========
This file contains information about threadscope profiling for Mercury.
1. Contact Info
2. Supported Systems.
3. Threadscope Profiling Tools
Contact Info
------------
Paul Bone
pbone@csse.unimelb.edu.au
Mercury Project
mercury@csse.unimelb.edu.au
http://www.mercury.csse.unimelb.edu.au
Supported Systems
-----------------
Threadscope uses the RDTSCP or RDTSC instructions found on some x86 and x86_64
processors to get fast, high precision timing information. These instructions
read the time stamp counter (TSC), this is incremented for every clock cycle.
Processors must increment this at a constant rate, regardless of their power
state, (see /proc/cpuinfo for constant_tsc).
TSC must also be synchronised between processors in the same system, although
it may be possible to work around this, let me know if you have such a system
(See contact info).
AMD processors do not seem to store their clock frequency in their brand ID
string. On these systems Theadscope profiles are not to scale since clock
counts cannot be converted into time in nanoseconds. The threadscope profile
will count one nanosecond for each clock tick.
I have had success with the following processors:
Intel Core2
Intel Xeon CPU X5472 (in a dual socket system).
Processors that do not work correctly:
AMD Athlon 64 X2
Threadscope Profiling Tools
---------------------------
Mercury supports threadscope profiling. See the profiling section in the user
guide.
The Threadscope profiling tools are written in Haskell and are known to work
with GHC 6.10. threadscope depends upon the following Haskell libraries:
array
binary
containers
filepath
ghc-events
gtk2hs
mtl
Many of these will be provided with GHC or packaged for/by your operating
system.
ghc-events is not packaged by most operating systems at this stage, It can be
retrieved from hackage:
http://hackage.haskell.org/package/ghc-events
threadscope itself can also be retrieved from hackage:
http://hackage.haskell.org/package/threadscope
Information about how to install Haskell packages can be found here:
http://haskell.org/haskellwiki/Cabal/How_to_install_a_Cabal_package