From dce566553cffef61d49ad135f2b5a9e1d96fe34f Mon Sep 17 00:00:00 2001 From: =?utf8?q?P=C3=A1draig=20Brady?= Date: Sat, 5 Apr 2025 21:48:05 +0100 Subject: [PATCH] timeout: remove dependence on libm This was seen to add about 100,000 ns to the startup time, on a 2.6 GHz i7-5600U with glibc 2.40. * .gitignore: Remove /lib/fenv.h. * bootstrap.conf: Remove fenv-rounding and signbit deps. * src/local.mk: Remove fenv lib dependency. * src/timeout.c (is_negative): A new helper function to be equivalent of signbit in the underflow case. (parse_duration): Remove the rounding up logic, as a nanosecond here or there has no significance. --- .gitignore | 1 - bootstrap.conf | 2 -- src/local.mk | 3 --- src/timeout.c | 36 +++++++++++------------------------- 4 files changed, 11 insertions(+), 31 deletions(-) diff --git a/.gitignore b/.gitignore index 4dc39ae551..f4a17ad044 100644 --- a/.gitignore +++ b/.gitignore @@ -67,7 +67,6 @@ /lib/errno.h /lib/error.h /lib/fcntl.h -/lib/fenv.h /lib/float.h /lib/fnmatch.h /lib/getopt-cdefs.h diff --git a/bootstrap.conf b/bootstrap.conf index 3c133ef714..c99838e95a 100644 --- a/bootstrap.conf +++ b/bootstrap.conf @@ -99,7 +99,6 @@ gnulib_modules=" fdatasync fdopen fdutimensat - fenv-rounding file-has-acl file-type fileblocks @@ -243,7 +242,6 @@ gnulib_modules=" settime sig2str sigaction - signbit skipchars smack ssize_t diff --git a/src/local.mk b/src/local.mk index 0a4e3af432..fd9dc81c27 100644 --- a/src/local.mk +++ b/src/local.mk @@ -257,9 +257,6 @@ src_stat_LDADD += $(LIB_SELINUX) # for nvlist_lookup_uint64_array src_stat_LDADD += $(LIB_NVPAIR) -# for fegetround, fesetround -src_timeout_LDADD += $(FENV_ROUNDING_LIBM) - # for gettime, settime, tempname, utimecmp, utimens copy_ldadd += $(CLOCK_TIME_LIB) src_date_LDADD += $(CLOCK_TIME_LIB) diff --git a/src/timeout.c b/src/timeout.c index 5947c19421..fe8eb45596 100644 --- a/src/timeout.c +++ b/src/timeout.c @@ -45,9 +45,8 @@ Written by Pádraig Brady. */ #include -#include +#include #include -#include #include #include #include @@ -354,32 +353,25 @@ apply_time_suffix (double *x, char suffix_char) return true; } +ATTRIBUTE_PURE static bool +is_negative (char const *num) +{ + while (*num && isspace (to_uchar (*num))) + num++; + return *num == '-'; +} + static double parse_duration (char const *str) { - /* If possible tell strtod to round up, so that we always wait at - least as long as STR specifies. Although Standard C requires - FENV_ACCESS ON, don't bother if using GCC as it warns. */ -#ifdef FE_UPWARD -# if !defined __GNUC__ && 199901 <= __STDC_VERSION__ -# pragma STDC FENV_ACCESS ON -# endif - int round = fegetround (); - fesetround (FE_UPWARD); -#endif - char *ep; double duration = cl_strtod (str, &ep); -#ifdef FE_UPWARD - fesetround (round); -#endif - if (ep == str /* Nonnegative interval. */ || ! (0 <= duration) /* The interval did not underflow to -0. */ - || (signbit (duration) && errno == ERANGE) + || (errno == ERANGE && is_negative (str)) /* No extra chars after the number and an optional s,m,h,d char. */ || (*ep && *(ep + 1)) /* Check any suffix char and update timeout based on the suffix. */ @@ -391,16 +383,10 @@ parse_duration (char const *str) /* Do not let the duration underflow to 0, as 0 disables the timeout. Use 2**-30 instead of 0; settimeout will round it up to 1 ns, - whereas 1e-9 might double-round to 2 ns. + whereas 1e-9 might double-round to 2 ns. */ - If FE_UPWARD is defined, this code is not needed on glibc as its - strtod rounds upward correctly. Although this code might not be - needed on non-glibc platforms too, it's too much trouble to - worry about that. */ -#if !defined FE_UPWARD || !defined __GLIBC__ if (duration == 0 && errno == ERANGE) duration = 9.313225746154785e-10; -#endif return duration; } -- 2.47.3