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| author | Vito Caputo <vcaputo@pengaru.com> | 2017-07-17 15:05:52 -0700 |
|---|---|---|
| committer | Lennart Poettering <lennart@poettering.net> | 2017-07-18 00:05:52 +0200 |
| commit | db3f45e2d2586d78f942a43e661415bc50716d11 (patch) | |
| tree | 4dcba7af3a20406228a49a50f7c24838ba9c3fde /src/basic/string-util.c | |
| parent | e758bc9132305b4398471bf7002ccd8b45b2b5a4 (diff) | |
| download | systemd-db3f45e2d2586d78f942a43e661415bc50716d11.tar.gz | |
basic: use _unlocked() stdio in strip_tab_ansi() (#6385)
Trivial performance boost by explicitly bypassing the implicit
locking of stdio.
This significantly affects common cases of `journalctl` usage:
Before:
# time ./journalctl -b -1 > /dev/null
real 0m26.628s
user 0m26.495s
sys 0m0.125s
# time ./journalctl -b -1 > /dev/null
real 0m27.069s
user 0m26.936s
sys 0m0.134s
# time ./journalctl -b -1 > /dev/null
real 0m26.727s
user 0m26.607s
sys 0m0.119s
After:
# time ./journalctl -b -1 > /dev/null
real 0m23.394s
user 0m23.244s
sys 0m0.142s
# time ./journalctl -b -1 > /dev/null
real 0m23.283s
user 0m23.160s
sys 0m0.121s
# time ./journalctl -b -1 > /dev/null
real 0m23.274s
user 0m23.125s
sys 0m0.144s
Fixes https://github.com/systemd/systemd/issues/6341
Diffstat (limited to 'src/basic/string-util.c')
| -rw-r--r-- | src/basic/string-util.c | 19 |
1 files changed, 12 insertions, 7 deletions
diff --git a/src/basic/string-util.c b/src/basic/string-util.c index 9d2f4bc8f9..c3d97740d2 100644 --- a/src/basic/string-util.c +++ b/src/basic/string-util.c @@ -635,6 +635,11 @@ char *strip_tab_ansi(char **ibuf, size_t *_isz) { if (!f) return NULL; + /* Note we use the _unlocked() stdio variants on f for performance + * reasons. It's safe to do so since we created f here and it + * doesn't leave our scope. + */ + for (i = *ibuf; i < *ibuf + isz + 1; i++) { switch (state) { @@ -645,21 +650,21 @@ char *strip_tab_ansi(char **ibuf, size_t *_isz) { else if (*i == '\x1B') state = STATE_ESCAPE; else if (*i == '\t') - fputs(" ", f); + fputs_unlocked(" ", f); else - fputc(*i, f); + fputc_unlocked(*i, f); break; case STATE_ESCAPE: if (i >= *ibuf + isz) { /* EOT */ - fputc('\x1B', f); + fputc_unlocked('\x1B', f); break; } else if (*i == '[') { state = STATE_BRACKET; begin = i + 1; } else { - fputc('\x1B', f); - fputc(*i, f); + fputc_unlocked('\x1B', f); + fputc_unlocked(*i, f); state = STATE_OTHER; } @@ -669,8 +674,8 @@ char *strip_tab_ansi(char **ibuf, size_t *_isz) { if (i >= *ibuf + isz || /* EOT */ (!(*i >= '0' && *i <= '9') && *i != ';' && *i != 'm')) { - fputc('\x1B', f); - fputc('[', f); + fputc_unlocked('\x1B', f); + fputc_unlocked('[', f); state = STATE_OTHER; i = begin-1; } else if (*i == 'm') |