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src/share/vm/runtime/perfMemory.hpp@0715f0cf171d (annotated)

src/share/vm/runtime/perfMemory.hpp

Fri, 08 Oct 2010 09:29:09 -0700

author

jcoomes

date

Fri, 08 Oct 2010 09:29:09 -0700

changeset 2198

0715f0cf171d

parent 1907

c18cbe5936b8

child 2314

f95d63e2154a

permissions

-rw-r--r--

Merge

duke@435	1	/*
trims@1907	2	* Copyright (c) 2001, 2008, Oracle and/or its affiliates. All rights reserved.
duke@435	3	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435	4	*
duke@435	5	* This code is free software; you can redistribute it and/or modify it
duke@435	6	* under the terms of the GNU General Public License version 2 only, as
duke@435	7	* published by the Free Software Foundation.
duke@435	8	*
duke@435	9	* This code is distributed in the hope that it will be useful, but WITHOUT
duke@435	10	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435	11	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
duke@435	12	* version 2 for more details (a copy is included in the LICENSE file that
duke@435	13	* accompanied this code).
duke@435	14	*
duke@435	15	* You should have received a copy of the GNU General Public License version
duke@435	16	* 2 along with this work; if not, write to the Free Software Foundation,
duke@435	17	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435	18	*
trims@1907	19	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
trims@1907	20	* or visit www.oracle.com if you need additional information or have any
trims@1907	21	* questions.
duke@435	22	*
duke@435	23	*/
duke@435	24
duke@435	25	/*
duke@435	26	* PerfData Version Constants
duke@435	27	* - Major Version - change whenever the structure of PerfDataEntry changes
duke@435	28	* - Minor Version - change whenever the data within the PerfDataEntry
duke@435	29	* structure changes. for example, new unit or variability
duke@435	30	* values are added or new PerfData subtypes are added.
duke@435	31	*/
duke@435	32	#define PERFDATA_MAJOR_VERSION 2
duke@435	33	#define PERFDATA_MINOR_VERSION 0
duke@435	34
duke@435	35	/* Byte order of the PerfData memory region. The byte order is exposed in
duke@435	36	* the PerfData memory region as the data in the memory region may have
duke@435	37	* been generated by a little endian JVM implementation. Tracking the byte
duke@435	38	* order in the PerfData memory region allows Java applications to adapt
duke@435	39	* to the native byte order for monitoring purposes. This indicator is
duke@435	40	* also useful when a snapshot of the PerfData memory region is shipped
duke@435	41	* to a machine with a native byte order different from that of the
duke@435	42	* originating machine.
duke@435	43	*/
duke@435	44	#define PERFDATA_BIG_ENDIAN 0
duke@435	45	#define PERFDATA_LITTLE_ENDIAN 1
duke@435	46
duke@435	47	/*
duke@435	48	* The PerfDataPrologue structure is known by the PerfDataBuffer Java class
duke@435	49	* libraries that read the PerfData memory region. The size and the position
duke@435	50	* of the fields must be changed along with their counterparts in the
duke@435	51	* PerfDataBuffer Java class. The first four bytes of this structure
duke@435	52	* should never change, or compatibility problems between the monitoring
duke@435	53	* applications and Hotspot VMs will result. The reserved fields are
duke@435	54	* available for future enhancements.
duke@435	55	*/
duke@435	56	typedef struct {
duke@435	57	jint magic; // magic number - 0xcafec0c0
duke@435	58	jbyte byte_order; // byte order of the buffer
duke@435	59	jbyte major_version; // major and minor version numbers
duke@435	60	jbyte minor_version;
duke@435	61	jbyte accessible; // ready to access
duke@435	62	jint used; // number of PerfData memory bytes used
duke@435	63	jint overflow; // number of bytes of overflow
duke@435	64	jlong mod_time_stamp; // time stamp of last structural modification
duke@435	65	jint entry_offset; // offset of the first PerfDataEntry
duke@435	66	jint num_entries; // number of allocated PerfData entries
duke@435	67	} PerfDataPrologue;
duke@435	68
duke@435	69	/* The PerfDataEntry structure defines the fixed portion of an entry
duke@435	70	* in the PerfData memory region. The PerfDataBuffer Java libraries
duke@435	71	* are aware of this structure and need to be changed when this
duke@435	72	* structure changes.
duke@435	73	*/
duke@435	74	typedef struct {
duke@435	75
duke@435	76	jint entry_length; // entry length in bytes
duke@435	77	jint name_offset; // offset of the data item name
duke@435	78	jint vector_length; // length of the vector. If 0, then scalar
duke@435	79	jbyte data_type; // type of the data item -
duke@435	80	// 'B','Z','J','I','S','C','D','F','V','L','['
duke@435	81	jbyte flags; // flags indicating misc attributes
duke@435	82	jbyte data_units; // unit of measure for the data type
duke@435	83	jbyte data_variability; // variability classification of data type
duke@435	84	jint data_offset; // offset of the data item
duke@435	85
duke@435	86	/*
duke@435	87	body of PerfData memory entry is variable length
duke@435	88
duke@435	89	jbyte[name_length] data_name; // name of the data item
duke@435	90	jbyte[pad_length] data_pad; // alignment of data item
duke@435	91	j<data_type>[data_length] data_item; // array of appropriate types.
duke@435	92	// data_length is > 1 only when the
duke@435	93	// data_type is T_ARRAY.
duke@435	94	*/
duke@435	95	} PerfDataEntry;
duke@435	96
duke@435	97	// Prefix of performance data file.
kvn@869	98	extern const char PERFDATA_NAME[];
duke@435	99
duke@435	100	// UINT_CHARS contains the number of characters holding a process id
duke@435	101	// (i.e. pid). pid is defined as unsigned "int" so the maximum possible pid value
duke@435	102	// would be 2^32 - 1 (4294967295) which can be represented as a 10 characters
duke@435	103	// string.
duke@435	104	static const size_t UINT_CHARS = 10;
duke@435	105
duke@435	106	/* the PerfMemory class manages creation, destruction,
duke@435	107	* and allocation of the PerfData region.
duke@435	108	*/
duke@435	109	class PerfMemory : AllStatic {
duke@435	110	friend class VMStructs;
duke@435	111	private:
duke@435	112	static char* _start;
duke@435	113	static char* _end;
duke@435	114	static char* _top;
duke@435	115	static size_t _capacity;
duke@435	116	static PerfDataPrologue* _prologue;
duke@435	117	static jint _initialized;
duke@435	118
duke@435	119	static void create_memory_region(size_t sizep);
duke@435	120	static void delete_memory_region();
duke@435	121
duke@435	122	public:
duke@435	123	enum PerfMemoryMode {
duke@435	124	PERF_MODE_RO = 0,
duke@435	125	PERF_MODE_RW = 1
duke@435	126	};
duke@435	127
duke@435	128	static char* alloc(size_t size);
duke@435	129	static char* start() { return _start; }
duke@435	130	static char* end() { return _end; }
duke@435	131	static size_t used() { return (size_t) (_top - _start); }
duke@435	132	static size_t capacity() { return _capacity; }
duke@435	133	static bool is_initialized() { return _initialized != 0; }
duke@435	134	static bool contains(char* addr) {
duke@435	135	return ((_start != NULL) && (addr >= _start) && (addr < _end));
duke@435	136	}
duke@435	137	static void mark_updated();
duke@435	138
duke@435	139	// methods for attaching to and detaching from the PerfData
duke@435	140	// memory segment of another JVM process on the same system.
duke@435	141	static void attach(const char* user, int vmid, PerfMemoryMode mode,
duke@435	142	char** addrp, size_t* size, TRAPS);
duke@435	143	static void detach(char* addr, size_t bytes, TRAPS);
duke@435	144
duke@435	145	static void initialize();
duke@435	146	static void destroy();
duke@435	147	static void set_accessible(bool value) {
duke@435	148	if (UsePerfData) {
duke@435	149	_prologue->accessible = value;
duke@435	150	}
duke@435	151	}
duke@435	152
duke@435	153	// filename of backing store or NULL if none.
duke@435	154	static char* backing_store_filename();
duke@435	155
duke@435	156	// returns the complete file path of hsperfdata.
duke@435	157	// the caller is expected to free the allocated memory.
duke@435	158	static char* get_perfdata_file_path();
duke@435	159	};
duke@435	160
duke@435	161	void perfMemory_init();
duke@435	162	void perfMemory_exit();