From 6765d5d34d126b26d55e2d73dac4dfec5e6d6241 Mon Sep 17 00:00:00 2001 From: Siddhesh Poyarekar Date: Sat, 31 Dec 2016 23:34:04 +0530 Subject: Enhance --enable-tunables to select tunables frontend at build time At the GNU Tools Cauldron 2016, the state of the current tunables patchset was considered OK with the addition of a way to select the frontend to be used for the tunables. That is, to avoid being locked in to one type of frontend initially, it should be possible to build tunables with a different frontend with something as simple as a configure switch. To that effect, this patch enhances the --enable-tunables option to accept more values than just 'yes' or 'no'. The current frontend (and default when enable-tunables is 'yes') is called 'valstring', to select the frontend where a single environment variable is set to a colon-separated value string. More such frontends can be added in future. * Makeconfig (have-tunables): Check for non-negative instead of positive. * configure.ac: Add 'valstring' as a valid value for --enable-tunables. * configure: Regenerate. * elf/Makefile (have-tunables): Check for non-negative instead of positive. (CPPFLAGS-dl-tunables.c): Define TUNABLES_FRONTEND for dl-tunables.c. * elf/dl-tunables.c (GLIBC_TUNABLES): Define only when TUNABLES_FRONTEND == TUNABLES_FRONTEND_valstring. (tunables_strdup): Likewise. (disable_tunables): Likewise. (parse_tunables): Likewise. (__tunables_init): Process GLIBC_TUNABLES envvar only when. TUNABLES_FRONTEND == TUNABLES_FRONTEND_valstring. * elf/dl-tunables.h (TUNABLES_FRONTEND_valstring): New macro. (TUNABLES_FRONTEND_yes): New macro, define as TUNABLES_FRONTEND_valstring by default. * manual/install.texi: Document new acceptable values for --enable-tunables. * INSTALL: Regenerate. --- INSTALL | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) (limited to 'INSTALL') diff --git a/INSTALL b/INSTALL index 25619fc..55d52c5 100644 --- a/INSTALL +++ b/INSTALL @@ -172,7 +172,23 @@ will be used, and CFLAGS sets optimization options for the compiler. '--enable-tunables' Tunables support allows additional library parameters to be customized at runtime. This is an experimental feature and affects - startup time and is thus disabled by default. + startup time and is thus disabled by default. This option can take + the following values: + + 'no' + This is the default if the option is not passed to configure. + This disables tunables. + + 'yes' + This is the default if the option is passed to configure. + This enables tunables and selects the default frontend + (currently 'valstring'). + + 'valstring' + This enables tunables and selects the 'valstring' frontend for + tunables. This frontend allows users to specify tunables as a + colon-separated list in a single environment variable + 'GLIBC_TUNABLES'. '--build=BUILD-SYSTEM' '--host=HOST-SYSTEM' -- cgit v1.1