linux/scripts/kconfig/expr.h
Andi Kleen e66f25d7d1 Improve kconfig symbol hashing
While looking for something else I noticed that the symbol
hash function used by kconfig is quite poor. It doesn't
use any of the standard hash techniques but simply
adds up the string and then uses power of two masking,
which is both known to perform poorly.

The current x86 kconfig has over 7000 symbols.

When I instrumented it showed that the minimum hash chain
length was 16 and a significant number of them was over
30.

It didn't help that the hash table size was only 256 buckets.

This patch increases the hash table size to a larger prime
and switches to a FNV32 hash. I played around with a couple of hash
functions, but that one seemed to perform best with reasonable
hash table sizes.

Increasing the hash table size even further didn't
seem like a good idea, because there are a couple of global
walks which walk the complete hash table.

I also moved the unnamed bucket to 0. It's still the longest
of all the buckets (44 entries), but hopefully it's not
often hit except for the global walk which doesn't care.

The result is a much nicer distribution:
(first column bucket length, second number of buckets with that length)

1: 3505
2: 1236
3: 294
4: 52
5: 3
47: 1		<--- this is the unnamed symbols bucket

There are still some 5+ buckets, but increasing the hash table
even more would be likely not worth it.

This also cleans up the code slightly by removing hard coded
magic numbers.

I didn't notice a big performance difference either way
on my Nehalem system, but I presume it'll help somewhat
on slower systems.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>
2010-02-02 14:33:55 +01:00

228 lines
6.8 KiB
C

/*
* Copyright (C) 2002 Roman Zippel <zippel@linux-m68k.org>
* Released under the terms of the GNU GPL v2.0.
*/
#ifndef EXPR_H
#define EXPR_H
#ifdef __cplusplus
extern "C" {
#endif
#include <stdio.h>
#ifndef __cplusplus
#include <stdbool.h>
#endif
struct file {
struct file *next;
struct file *parent;
char *name;
int lineno;
int flags;
};
#define FILE_BUSY 0x0001
#define FILE_SCANNED 0x0002
typedef enum tristate {
no, mod, yes
} tristate;
enum expr_type {
E_NONE, E_OR, E_AND, E_NOT, E_EQUAL, E_UNEQUAL, E_LIST, E_SYMBOL, E_RANGE
};
union expr_data {
struct expr *expr;
struct symbol *sym;
};
struct expr {
enum expr_type type;
union expr_data left, right;
};
#define EXPR_OR(dep1, dep2) (((dep1)>(dep2))?(dep1):(dep2))
#define EXPR_AND(dep1, dep2) (((dep1)<(dep2))?(dep1):(dep2))
#define EXPR_NOT(dep) (2-(dep))
#define expr_list_for_each_sym(l, e, s) \
for (e = (l); e && (s = e->right.sym); e = e->left.expr)
struct expr_value {
struct expr *expr;
tristate tri;
};
struct symbol_value {
void *val;
tristate tri;
};
enum symbol_type {
S_UNKNOWN, S_BOOLEAN, S_TRISTATE, S_INT, S_HEX, S_STRING, S_OTHER
};
/* enum values are used as index to symbol.def[] */
enum {
S_DEF_USER, /* main user value */
S_DEF_AUTO, /* values read from auto.conf */
S_DEF_DEF3, /* Reserved for UI usage */
S_DEF_DEF4, /* Reserved for UI usage */
S_DEF_COUNT
};
struct symbol {
struct symbol *next;
char *name;
enum symbol_type type;
struct symbol_value curr;
struct symbol_value def[S_DEF_COUNT];
tristate visible;
int flags;
struct property *prop;
struct expr_value rev_dep;
};
#define for_all_symbols(i, sym) for (i = 0; i < SYMBOL_HASHSIZE; i++) for (sym = symbol_hash[i]; sym; sym = sym->next) if (sym->type != S_OTHER)
#define SYMBOL_CONST 0x0001 /* symbol is const */
#define SYMBOL_CHECK 0x0008 /* used during dependency checking */
#define SYMBOL_CHOICE 0x0010 /* start of a choice block (null name) */
#define SYMBOL_CHOICEVAL 0x0020 /* used as a value in a choice block */
#define SYMBOL_VALID 0x0080 /* set when symbol.curr is calculated */
#define SYMBOL_OPTIONAL 0x0100 /* choice is optional - values can be 'n' */
#define SYMBOL_WRITE 0x0200 /* ? */
#define SYMBOL_CHANGED 0x0400 /* ? */
#define SYMBOL_AUTO 0x1000 /* value from environment variable */
#define SYMBOL_CHECKED 0x2000 /* used during dependency checking */
#define SYMBOL_WARNED 0x8000 /* warning has been issued */
/* Set when symbol.def[] is used */
#define SYMBOL_DEF 0x10000 /* First bit of SYMBOL_DEF */
#define SYMBOL_DEF_USER 0x10000 /* symbol.def[S_DEF_USER] is valid */
#define SYMBOL_DEF_AUTO 0x20000 /* symbol.def[S_DEF_AUTO] is valid */
#define SYMBOL_DEF3 0x40000 /* symbol.def[S_DEF_3] is valid */
#define SYMBOL_DEF4 0x80000 /* symbol.def[S_DEF_4] is valid */
#define SYMBOL_MAXLENGTH 256
#define SYMBOL_HASHSIZE 9973
/* A property represent the config options that can be associated
* with a config "symbol".
* Sample:
* config FOO
* default y
* prompt "foo prompt"
* select BAR
* config BAZ
* int "BAZ Value"
* range 1..255
*/
enum prop_type {
P_UNKNOWN,
P_PROMPT, /* prompt "foo prompt" or "BAZ Value" */
P_COMMENT, /* text associated with a comment */
P_MENU, /* prompt associated with a menuconfig option */
P_DEFAULT, /* default y */
P_CHOICE, /* choice value */
P_SELECT, /* select BAR */
P_RANGE, /* range 7..100 (for a symbol) */
P_ENV, /* value from environment variable */
};
struct property {
struct property *next; /* next property - null if last */
struct symbol *sym; /* the symbol for which the property is associated */
enum prop_type type; /* type of property */
const char *text; /* the prompt value - P_PROMPT, P_MENU, P_COMMENT */
struct expr_value visible;
struct expr *expr; /* the optional conditional part of the property */
struct menu *menu; /* the menu the property are associated with
* valid for: P_SELECT, P_RANGE, P_CHOICE,
* P_PROMPT, P_DEFAULT, P_MENU, P_COMMENT */
struct file *file; /* what file was this property defined */
int lineno; /* what lineno was this property defined */
};
#define for_all_properties(sym, st, tok) \
for (st = sym->prop; st; st = st->next) \
if (st->type == (tok))
#define for_all_defaults(sym, st) for_all_properties(sym, st, P_DEFAULT)
#define for_all_choices(sym, st) for_all_properties(sym, st, P_CHOICE)
#define for_all_prompts(sym, st) \
for (st = sym->prop; st; st = st->next) \
if (st->text)
struct menu {
struct menu *next;
struct menu *parent;
struct menu *list;
struct symbol *sym;
struct property *prompt;
struct expr *dep;
unsigned int flags;
char *help;
struct file *file;
int lineno;
void *data;
};
#define MENU_CHANGED 0x0001
#define MENU_ROOT 0x0002
#ifndef SWIG
extern struct file *file_list;
extern struct file *current_file;
struct file *lookup_file(const char *name);
extern struct symbol symbol_yes, symbol_no, symbol_mod;
extern struct symbol *modules_sym;
extern struct symbol *sym_defconfig_list;
extern int cdebug;
struct expr *expr_alloc_symbol(struct symbol *sym);
struct expr *expr_alloc_one(enum expr_type type, struct expr *ce);
struct expr *expr_alloc_two(enum expr_type type, struct expr *e1, struct expr *e2);
struct expr *expr_alloc_comp(enum expr_type type, struct symbol *s1, struct symbol *s2);
struct expr *expr_alloc_and(struct expr *e1, struct expr *e2);
struct expr *expr_alloc_or(struct expr *e1, struct expr *e2);
struct expr *expr_copy(struct expr *org);
void expr_free(struct expr *e);
int expr_eq(struct expr *e1, struct expr *e2);
void expr_eliminate_eq(struct expr **ep1, struct expr **ep2);
tristate expr_calc_value(struct expr *e);
struct expr *expr_eliminate_yn(struct expr *e);
struct expr *expr_trans_bool(struct expr *e);
struct expr *expr_eliminate_dups(struct expr *e);
struct expr *expr_transform(struct expr *e);
int expr_contains_symbol(struct expr *dep, struct symbol *sym);
bool expr_depends_symbol(struct expr *dep, struct symbol *sym);
struct expr *expr_extract_eq_and(struct expr **ep1, struct expr **ep2);
struct expr *expr_extract_eq_or(struct expr **ep1, struct expr **ep2);
void expr_extract_eq(enum expr_type type, struct expr **ep, struct expr **ep1, struct expr **ep2);
struct expr *expr_trans_compare(struct expr *e, enum expr_type type, struct symbol *sym);
void expr_fprint(struct expr *e, FILE *out);
struct gstr; /* forward */
void expr_gstr_print(struct expr *e, struct gstr *gs);
static inline int expr_is_yes(struct expr *e)
{
return !e || (e->type == E_SYMBOL && e->left.sym == &symbol_yes);
}
static inline int expr_is_no(struct expr *e)
{
return e && (e->type == E_SYMBOL && e->left.sym == &symbol_no);
}
#endif
#ifdef __cplusplus
}
#endif
#endif /* EXPR_H */