From mboxrd@z Thu Jan 1 00:00:00 1970 From: Baruch Siach Date: Sun, 19 Jul 2015 12:33:00 +0300 Subject: [Buildroot] [PATCH] package/glibc: enable lock elision on x86_64 hosts In-Reply-To: <20150719112314.2d733eaf@free-electrons.com> References: <1426716071-27570-1-git-send-email-steven@uplinklabs.net> <1426716071-27570-2-git-send-email-steven@uplinklabs.net> <20150719112314.2d733eaf@free-electrons.com> Message-ID: <20150719093300.GG13027@tarshish> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: buildroot@busybox.net Hi Thomas, On Sun, Jul 19, 2015 at 11:23:14AM +0200, Thomas Petazzoni wrote: > On Wed, 18 Mar 2015 15:01:09 -0700, Steven Noonan wrote: > > Signed-off-by: Steven Noonan > > --- > > package/glibc/glibc.mk | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/package/glibc/glibc.mk b/package/glibc/glibc.mk > > index 0a37bb3..651711a 100644 > > --- a/package/glibc/glibc.mk > > +++ b/package/glibc/glibc.mk > > @@ -90,6 +90,7 @@ define GLIBC_CONFIGURE_CMDS > > --prefix=/usr \ > > --enable-shared \ > > $(if $(BR2_SOFT_FLOAT),--without-fp,--with-fp) \ > > + $(if $(BR2_x86_64),--enable-lock-elision,) \ > > What happens on x86-64 processors that don't have the HW support needed > for lock elision ? Does glibc gracefully falls back at runtime to > "normal" locks ? According to the code at sysdeps/unix/sysv/linux/x86/elision-conf.c, __elision_available is initialized from HAS_RTM which is evaluated at run-time (sysdeps/x86_64/multiarch/init-arch.h). baruch -- http://baruch.siach.name/blog/ ~. .~ Tk Open Systems =}------------------------------------------------ooO--U--Ooo------------{= - baruch at tkos.co.il - tel: +972.2.679.5364, http://www.tkos.co.il -