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Improve devd startup time, by tweaking some string handling routines that are

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heavily used when parsing config files.  Mostly these changes avoid making
temporary copies of the strings, and avoid doing byte at a time append
operations, on the most-used code path.

On a 1.2 GHz ARM processor this reduces the time to parse the config files
from 13 to 6 seconds.

Reviewed by:	imp
Approved by:	cognet (mentor)
This commit is contained in:
ian 2013-01-30 23:37:35 +00:00
parent 1ce2adadbb
commit 85fcf6286d
2 changed files with 32 additions and 25 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

52
sbin/devd/devd.cc
View File

@ -137,7 +137,7 @@ config cfg;
event_proc::event_proc() : _prio(-1)
{
// nothing
_epsvec.reserve(4);
}
event_proc::~event_proc()
@ -241,25 +241,18 @@ my_system(const char *command)
bool
action::do_action(config &c)
{
string s = c.expand_string(_cmd);
string s = c.expand_string(_cmd.c_str());
if (Dflag)
fprintf(stderr, "Executing '%s'\n", s.c_str());
my_system(s.c_str());
return (true);
}
match::match(config &c, const char *var, const char *re)
: _var(var), _re("^")
match::match(config &c, const char *var, const char *re) :
_inv(re[0] == '!'),
_var(var),
_re(c.expand_string(_inv ? re + 1 : re, "^", "$"))
{
if (!c.expand_string(string(re)).empty() &&
c.expand_string(string(re)).at(0) == '!') {
_re.append(c.expand_string(string(re)).substr(1));
_inv = 1;
} else {
_re.append(c.expand_string(string(re)));
_inv = 0;
}
_re.append("$");
regcomp(&_regex, _re.c_str(), REG_EXTENDED | REG_NOSUB | REG_ICASE);
}
@ -624,24 +617,37 @@ config::expand_one(const char *&src, string &dst)
do {
buffer.append(src++, 1);
} while (is_id_char(*src));
buffer.append("", 1);
dst.append(get_variable(buffer.c_str()));
}
const string
config::expand_string(const string &s)
config::expand_string(const char *src, const char *prepend, const char *append)
{
const char *src;
const char *var_at;
string dst;
src = s.c_str();
while (*src) {
if (*src == '$')
expand_one(src, dst);
else
dst.append(src++, 1);
/*
* 128 bytes is enough for 2427 of 2438 expansions that happen
* while parsing config files, as tested on 2013-01-30.
*/
dst.reserve(128);
if (prepend != NULL)
dst = prepend;
for (;;) {
var_at = strchr(src, '$');
if (var_at == NULL) {
dst.append(src);
break;
}
dst.append(src, var_at - src);
src = var_at;
expand_one(src, dst);
}
dst.append("", 1);
if (append != NULL)
dst.append(append);
return (dst);
}

5
sbin/devd/devd.hh
View File

@ -90,9 +90,9 @@ public:
virtual bool do_match(config &);
virtual bool do_action(config &) { return true; }
private:
bool _inv;
std::string _var;
std::string _re;
bool _inv;
regex_t _regex;
};
@ -162,7 +162,8 @@ public:
void pop_var_table();
void set_variable(const char *var, const char *val);
const std::string &get_variable(const std::string &var);
const std::string expand_string(const std::string &var);
const std::string expand_string(const char * var,
const char * prepend = NULL, const char * append = NULL);
char *set_vars(char *);
void find_and_execute(char);
protected: