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| author | Tom Lane | 2018-10-03 14:18:15 +0000 |
|---|---|---|
| committer | Tom Lane | 2018-10-03 14:18:15 +0000 |
| commit | abd9ca377d669a6e0560e854d7e987438d0e612e (patch) | |
| tree | 26ff0086736a801c8be7d15bad9d1a6894116ebf /configure | |
| parent | 9bc9f72b28fe4d2c22244f3443af8f1b98b56474 (diff) | |
Make assorted performance improvements in snprintf.c.
In combination, these changes make our version of snprintf as fast
or faster than most platforms' native snprintf, except for cases
involving floating-point conversion (which we still delegate to
the native sprintf). The speed penalty for a float conversion
is down to around 10% though, much better than before.
Notable changes:
* Rather than always parsing the format twice to see if it contains
instances of %n$, do the extra scan only if we actually find a $.
This obviously wins for non-localized formats, and even when there
is use of %n$, we can avoid scanning text before the first % twice.
* Use strchrnul() if available to find the next %, and emit the
literal text between % escapes as strings rather than char-by-char.
* Create a bespoke function (dopr_outchmulti) for the common case
of emitting N copies of the same character, in place of writing
loops around dopr_outch.
* Simplify construction of the format string for invocations of sprintf
for floats.
* Const-ify some internal functions, and avoid unnecessary use of
pass-by-reference arguments.
Patch by me, reviewed by Andres Freund
Discussion: https://postgr.es/m/11787.1534530779@sss.pgh.pa.us
Diffstat (limited to 'configure')
| -rwxr-xr-x | configure | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/configure b/configure index 6414ec1ea6d..0448c6bfebf 100755 --- a/configure +++ b/configure @@ -15100,7 +15100,7 @@ fi LIBS_including_readline="$LIBS" LIBS=`echo "$LIBS" | sed -e 's/-ledit//g' -e 's/-lreadline//g'` -for ac_func in cbrt clock_gettime fdatasync getifaddrs getpeerucred getrlimit mbstowcs_l memmove poll posix_fallocate ppoll pstat pthread_is_threaded_np readlink setproctitle setproctitle_fast setsid shm_open symlink sync_file_range utime utimes wcstombs_l +for ac_func in cbrt clock_gettime fdatasync getifaddrs getpeerucred getrlimit mbstowcs_l memmove poll posix_fallocate ppoll pstat pthread_is_threaded_np readlink setproctitle setproctitle_fast setsid shm_open strchrnul symlink sync_file_range utime utimes wcstombs_l do : as_ac_var=`$as_echo "ac_cv_func_$ac_func" | $as_tr_sh` ac_fn_c_check_func "$LINENO" "$ac_func" "$as_ac_var" |