Date: Mon, 07 Mar 2005 13:47:42 -0700 From: Scott Long <scottl@samsco.org> To: obrien@FreeBSD.org Cc: John Baldwin <jhb@FreeBSD.org> Subject: Re: cvs commit: src/sys/kern kern_sig.c Message-ID: <422CBDEE.7020307@samsco.org> In-Reply-To: <20050307195156.GA18850@dragon.nuxi.com> References: <200503021343.j22DhpQ3075008@repoman.freebsd.org> <200503020915.28512.jhb@FreeBSD.org> <4226446B.7020406@freebsd.org> <61ac46c154aa515a692308440dd1141d@FreeBSD.org> <422710DD.1070203@freebsd.org> <422719E0.10703@samsco.org> <20050307195156.GA18850@dragon.nuxi.com>
next in thread | previous in thread | raw e-mail | index | archive | help
David O'Brien wrote: > On Thu, Mar 03, 2005 at 07:06:24AM -0700, Scott Long wrote: > >>a bit. Also, there is talk about increasing the default kstack size due >>to all of the extra inlining that the compiler does with the -O2 option > > > I'd love more details on the extra inlining people are seeing with -O2. > (i.e. specifics) -O2 is not supose to do extra function inlining. That > is suppose to be a -O3 thing. > > From the GCC manual: > > -O3 Optimize yet more. > -O3 turns on all optimizations specified by -O2 and also turns on the > -finline-functions, -fweb and -frename-registers options. > > -O2 Optimize even more. > GCC performs nearly all supported optimizations that do not involve a > space-speed tradeoff. The compiler does not perform loop unrolling or > function inlining when you specify -O2. As compared to -O, this > option increases both compilation time and the performance of the > generated code. > ..snip.. > > The -O2 options that affect size are: > -falign-functions -falign-jumps -falign-loops -falign-labels > -freorder-blocks -fprefetch-loop-arrays Talk to Bill Paul about the massive amount of inlining that is happening in the ieee80211 ioctl code, and the no_inline directives he had to use to kludge around it. Scott
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?422CBDEE.7020307>