test: Optimize operator lookup.

The linear search using strcmp() shows up in pmcstat for several percent.

Split the operators into lengths and whether they start with '-' and compare
bytes using == instead of strcmp().

A simple test

sh -c 'i=0; w=$(printf %0100d 7); while [ "$i" -lt 1000000 ]; do
    v=$(printf %sx%s "$w" "$w"); i=$((i+1)); done'

is over 4% faster on an amd64 bhyve VM.
This commit is contained in:
Jilles Tjoelker 2016-01-30 19:59:58 +00:00
parent d52f763c21
commit f1602fa511
Notes: svn2git 2020-12-20 02:59:44 +00:00
svn path=/head/; revision=295082

View File

@ -120,51 +120,53 @@ enum token {
#define TOKEN_TYPE(token) ((token) & 0xff00)
static struct t_op {
char op_text[4];
static const struct t_op {
char op_text[2];
short op_num;
} const ops [] = {
{"-r", FILRD},
{"-w", FILWR},
{"-x", FILEX},
{"-e", FILEXIST},
{"-f", FILREG},
{"-d", FILDIR},
{"-c", FILCDEV},
{"-b", FILBDEV},
{"-p", FILFIFO},
{"-u", FILSUID},
{"-g", FILSGID},
{"-k", FILSTCK},
{"-s", FILGZ},
{"-t", FILTT},
{"-z", STREZ},
{"-n", STRNZ},
{"-h", FILSYM}, /* for backwards compat */
{"-O", FILUID},
{"-G", FILGID},
{"-L", FILSYM},
{"-S", FILSOCK},
} ops1[] = {
{"=", STREQ},
{"==", STREQ},
{"!=", STRNE},
{"<", STRLT},
{">", STRGT},
{"-eq", INTEQ},
{"-ne", INTNE},
{"-ge", INTGE},
{"-gt", INTGT},
{"-le", INTLE},
{"-lt", INTLT},
{"-nt", FILNT},
{"-ot", FILOT},
{"-ef", FILEQ},
{"!", UNOT},
{"-a", BAND},
{"-o", BOR},
{"(", LPAREN},
{")", RPAREN},
{"", 0}
}, opsm1[] = {
{"r", FILRD},
{"w", FILWR},
{"x", FILEX},
{"e", FILEXIST},
{"f", FILREG},
{"d", FILDIR},
{"c", FILCDEV},
{"b", FILBDEV},
{"p", FILFIFO},
{"u", FILSUID},
{"g", FILSGID},
{"k", FILSTCK},
{"s", FILGZ},
{"t", FILTT},
{"z", STREZ},
{"n", STRNZ},
{"h", FILSYM}, /* for backwards compat */
{"O", FILUID},
{"G", FILGID},
{"L", FILSYM},
{"S", FILSOCK},
{"a", BAND},
{"o", BOR},
}, ops2[] = {
{"==", STREQ},
{"!=", STRNE},
}, opsm2[] = {
{"eq", INTEQ},
{"ne", INTNE},
{"ge", INTGE},
{"gt", INTGT},
{"le", INTLE},
{"lt", INTLT},
{"nt", FILNT},
{"ot", FILOT},
{"ef", FILEQ},
};
static int nargc;
@ -416,35 +418,71 @@ filstat(char *nm, enum token mode)
}
}
static enum token
t_lex(char *s)
static int
find_op_1char(const struct t_op *op, const struct t_op *end, const char *s)
{
struct t_op const *op = ops;
char c;
if (s == 0) {
return EOI;
}
while (*op->op_text) {
if (strcmp(s, op->op_text) == 0) {
if (((TOKEN_TYPE(op->op_num) == UNOP ||
TOKEN_TYPE(op->op_num) == BUNOP)
&& isunopoperand()) ||
(op->op_num == LPAREN && islparenoperand()) ||
(op->op_num == RPAREN && isrparenoperand()))
break;
c = s[0];
while (op != end) {
if (c == *op->op_text)
return op->op_num;
}
op++;
}
return OPERAND;
}
static int
find_op_2char(const struct t_op *op, const struct t_op *end, const char *s)
{
while (op != end) {
if (s[0] == op->op_text[0] && s[1] == op->op_text[1])
return op->op_num;
op++;
}
return OPERAND;
}
static int
find_op(const char *s)
{
if (s[0] == '\0')
return OPERAND;
else if (s[1] == '\0')
return find_op_1char(ops1, (&ops1)[1], s);
else if (s[2] == '\0')
return s[0] == '-' ? find_op_1char(opsm1, (&opsm1)[1], s + 1) :
find_op_2char(ops2, (&ops2)[1], s);
else if (s[3] == '\0')
return s[0] == '-' ? find_op_2char(opsm2, (&opsm2)[1], s + 1) :
OPERAND;
else
return OPERAND;
}
static enum token
t_lex(char *s)
{
int num;
if (s == 0) {
return EOI;
}
num = find_op(s);
if (((TOKEN_TYPE(num) == UNOP || TOKEN_TYPE(num) == BUNOP)
&& isunopoperand()) ||
(num == LPAREN && islparenoperand()) ||
(num == RPAREN && isrparenoperand()))
return OPERAND;
return num;
}
static int
isunopoperand(void)
{
struct t_op const *op = ops;
char *s;
char *t;
int num;
if (nargc == 1)
return 1;
@ -452,20 +490,16 @@ isunopoperand(void)
if (nargc == 2)
return parenlevel == 1 && strcmp(s, ")") == 0;
t = *(t_wp + 2);
while (*op->op_text) {
if (strcmp(s, op->op_text) == 0)
return TOKEN_TYPE(op->op_num) == BINOP &&
(parenlevel == 0 || t[0] != ')' || t[1] != '\0');
op++;
}
return 0;
num = find_op(s);
return TOKEN_TYPE(num) == BINOP &&
(parenlevel == 0 || t[0] != ')' || t[1] != '\0');
}
static int
islparenoperand(void)
{
struct t_op const *op = ops;
char *s;
int num;
if (nargc == 1)
return 1;
@ -474,12 +508,8 @@ islparenoperand(void)
return parenlevel == 1 && strcmp(s, ")") == 0;
if (nargc != 3)
return 0;
while (*op->op_text) {
if (strcmp(s, op->op_text) == 0)
return TOKEN_TYPE(op->op_num) == BINOP;
op++;
}
return 0;
num = find_op(s);
return TOKEN_TYPE(num) == BINOP;
}
static int