0ad/source/lib/res/file/trace.h
janwas 871cdb6ef9 # SwEng (reduce full recompiles by splitting up master error header)
- error codes now accessed as ERR::NO_MEM, INFO::OK etc.
- no more X-macros => the above are now recognized by visual assist
- error codes are defined by the module originating them (lib_errors has
some generic ones)
  => no full rebuild when adding some
- error descriptions are now in C++ files => can be changed without full
rebuild

added AT_STARTUP in lib.h.

This was SVN commit r4374.
2006-09-22 13:19:40 +00:00

104 lines
3.0 KiB
C++

/**
* =========================================================================
* File : trace.h
* Project : 0 A.D.
* Description : allows recording and 'playing back' a sequence of
* : I/Os - useful for benchmarking and archive builder.
*
* @author Jan.Wassenberg@stud.uni-karlsruhe.de
* =========================================================================
*/
/*
* Copyright (c) 2006 Jan Wassenberg
*
* Redistribution and/or modification are also permitted under the
* terms of the GNU General Public License as published by the
* Free Software Foundation (version 2 or later, at your option).
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
*/
#ifndef TRACE_H__
#define TRACE_H__
namespace ERR
{
const LibError TRACE_EMPTY = -110500;
}
extern void trace_enable(bool want_enabled);
extern void trace_shutdown();
extern void trace_notify_io(const char* P_fn, size_t size, uint flags);
extern void trace_notify_free(const char* P_fn, size_t size);
// TraceEntry operation type.
// note: rather than only a list of accessed files, we also need to
// know the application's behavior WRT caching (e.g. when it releases
// cached buffers). this is necessary so that our simulation can
// yield the same behavior.
enum TraceOp
{
TO_IO,
TO_FREE,
};
// stores one event that is relevant for file IO / caching.
//
// size-optimized a bit since these are all kept in memory
// (to prevent trace file writes from affecting other IOs)
struct TraceEntry
{
// note: float instead of double for nice 16 byte struct size
float timestamp; // returned by get_time before operation starts
const char* atom_fn; // path+name of affected file
// rationale: store size in the trace because other applications
// that use this trace format but not our IO code wouldn't know
// size (since they cannot retrieve the file info given atom_fn).
size_t size; // of IO (usually the entire file)
uint op : 8; // operation - see TraceOp
uint flags : 24; // misc, e.g. file_io flags.
};
struct TraceRun
{
const TraceEntry* ents;
size_t num_ents;
};
struct Trace
{
// most recent first! (see rationale in source)
const TraceRun* runs;
size_t num_runs;
size_t total_ents;
};
extern void trace_get(Trace* t);
extern LibError trace_write_to_file(const char* trace_filename);
extern LibError trace_read_from_file(const char* trace_filename, Trace* t);
extern void trace_gen_random(size_t num_entries);
// simulate carrying out the entry's TraceOp to determine
// whether this IO would be satisfied by the file_buf cache.
extern bool trace_entry_causes_io(const TraceEntry* ent);
enum TraceRunFlags
{
TRF_SYNC_TO_TIMESTAMP = 1
};
// carry out all operations specified in the trace.
// if flags&TRF_SYNC_TO_TIMESTAMP, waits until timestamp for each event is
// reached; otherwise, they are run as fast as possible.
extern LibError trace_run(const char* trace_filename, uint flags = 0);
#endif // #ifndef TRACE_H__