binutils-gdb/gdb/target-dcache.c
Yao Qi 29453a1455 set/show code-cache
Similar to stack cache, in this patch, we add
TARGET_OBJECT_CODE_MEMORY to read code from target and add a new
option "set code-cache on|off" to optimize code accesses by
using the target memory cache.

In V4:
 - Remove "without affecting correctness" from NEWS and doc.
 - Replace "ON" with "on" in doc.
 - "access" -> "accesses".

In V3:
 - Rename functions and variables.
 - Update command help, doc and NEWS entry.
 - Invalidate cache on option transitions, to align with
   the behaviour of "stack-cache".  Since cache invalidation is
   transparent to users, users don't know option "stack-cache"
   transitions cause code cache invalidation.

V2 was reviewed by Doug.  There are some changes in V3, so I post it
here.

gdb:

2013-11-24  Yao Qi  <yao@codesourcery.com>

	* NEWS: Add note on new "set code-cache" option.
	* target-dcache.c (code_cache_enabled_1): New variable.
	(code_cache_enabled): New variable.
	(show_code_cache, set_code_cache): New function.
	(code_cache_enabled_p): New function.
	(_initialize_target_dcache): Register command.
	* target-dcache.h (code_cache_enabled_p): Declare.
	* target.c (memory_xfer_partial_1):Handle
	TARGET_OBJECT_CODE_MEMORY and code_cache_enabled.
	(target_read_code): New function.
	* target.h (enum target_object) <TARGET_OBJECT_CODE_MEMORY>:
	New.
	(target_read_code): Declare.

gdb/doc:

2013-11-24  Yao Qi  <yao@codesourcery.com>

	* gdb.texinfo (Caching Remote Data): Document new
	"set/show stack-cache" option.
2013-11-24 14:56:49 +08:00

200 lines
5.4 KiB
C

/* Copyright (C) 1992-2013 Free Software Foundation, Inc.
This file is part of GDB.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
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. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include "defs.h"
#include "target-dcache.h"
#include "gdbcmd.h"
#include "progspace.h"
/* The target dcache is kept per-address-space. This key lets us
associate the cache with the address space. */
static const struct address_space_data *target_dcache_aspace_key;
/* Clean up dcache, represented by ARG, which is associated with
ASPACE. */
static void
target_dcache_cleanup (struct address_space *aspace, void *arg)
{
dcache_free (arg);
}
/* Target dcache is initialized or not. */
int
target_dcache_init_p (void)
{
DCACHE *dcache = address_space_data (current_program_space->aspace,
target_dcache_aspace_key);
return (dcache != NULL);
}
/* Invalidate the target dcache. */
void
target_dcache_invalidate (void)
{
DCACHE *dcache = address_space_data (current_program_space->aspace,
target_dcache_aspace_key);
if (dcache != NULL)
dcache_invalidate (dcache);
}
/* Return the target dcache. Return NULL if target dcache is not
initialized yet. */
DCACHE *
target_dcache_get (void)
{
DCACHE *dcache = address_space_data (current_program_space->aspace,
target_dcache_aspace_key);
return dcache;
}
/* Return the target dcache. If it is not initialized yet, initialize
it. */
DCACHE *
target_dcache_get_or_init (void)
{
DCACHE *dcache = address_space_data (current_program_space->aspace,
target_dcache_aspace_key);
if (dcache == NULL)
{
dcache = dcache_init ();
set_address_space_data (current_program_space->aspace,
target_dcache_aspace_key, dcache);
}
return dcache;
}
/* The option sets this. */
static int stack_cache_enabled_1 = 1;
/* And set_stack_cache updates this.
The reason for the separation is so that we don't flush the cache for
on->on transitions. */
static int stack_cache_enabled = 1;
/* This is called *after* the stack-cache has been set.
Flush the cache for off->on and on->off transitions.
There's no real need to flush the cache for on->off transitions,
except cleanliness. */
static void
set_stack_cache (char *args, int from_tty, struct cmd_list_element *c)
{
if (stack_cache_enabled != stack_cache_enabled_1)
target_dcache_invalidate ();
stack_cache_enabled = stack_cache_enabled_1;
}
static void
show_stack_cache (struct ui_file *file, int from_tty,
struct cmd_list_element *c, const char *value)
{
fprintf_filtered (file, _("Cache use for stack accesses is %s.\n"), value);
}
/* Return true if "stack cache" is enabled, otherwise, return false. */
int
stack_cache_enabled_p (void)
{
return stack_cache_enabled;
}
/* The option sets this. */
static int code_cache_enabled_1 = 1;
/* And set_code_cache updates this.
The reason for the separation is so that we don't flush the cache for
on->on transitions. */
static int code_cache_enabled = 1;
/* This is called *after* the code-cache has been set.
Flush the cache for off->on and on->off transitions.
There's no real need to flush the cache for on->off transitions,
except cleanliness. */
static void
set_code_cache (char *args, int from_tty, struct cmd_list_element *c)
{
if (code_cache_enabled != code_cache_enabled_1)
target_dcache_invalidate ();
code_cache_enabled = code_cache_enabled_1;
}
/* Show option "code-cache". */
static void
show_code_cache (struct ui_file *file, int from_tty,
struct cmd_list_element *c, const char *value)
{
fprintf_filtered (file, _("Cache use for code accesses is %s.\n"), value);
}
/* Return true if "code cache" is enabled, otherwise, return false. */
int
code_cache_enabled_p (void)
{
return code_cache_enabled;
}
/* -Wmissing-prototypes */
extern initialize_file_ftype _initialize_target_dcache;
void
_initialize_target_dcache (void)
{
add_setshow_boolean_cmd ("stack-cache", class_support,
&stack_cache_enabled_1, _("\
Set cache use for stack access."), _("\
Show cache use for stack access."), _("\
When on, use the target memory cache for all stack access, regardless of any\n\
configured memory regions. This improves remote performance significantly.\n\
By default, caching for stack access is on."),
set_stack_cache,
show_stack_cache,
&setlist, &showlist);
add_setshow_boolean_cmd ("code-cache", class_support,
&code_cache_enabled_1, _("\
Set cache use for code segment access."), _("\
Show cache use for code segment access."), _("\
When on, use the target memory cache for all code segment accesses,\n\
regardless of any configured memory regions. This improves remote\n\
performance significantly. By default, caching for code segment\n\
access is on."),
set_code_cache,
show_code_cache,
&setlist, &showlist);
target_dcache_aspace_key
= register_address_space_data_with_cleanup (NULL,
target_dcache_cleanup);
}