Date: Wed, 3 Aug 2016 09:24:15 +0300 From: Andriy Gapon <avg@FreeBSD.org> To: Zaphod Beeblebrox <zbeeble@gmail.com>, FreeBSD Hackers <freebsd-hackers@FreeBSD.org> Subject: Re: How to get better debugging for the kernel. Message-ID: <d3c8ec3b-9b91-9f79-c7cf-ad1f6660a3bf@FreeBSD.org> In-Reply-To: <CACpH0Mcw1oTatUX3d7gJ4ys=dAj_y9C9vF_g110MrHVEup4mjQ@mail.gmail.com> References: <CACpH0Mcw1oTatUX3d7gJ4ys=dAj_y9C9vF_g110MrHVEup4mjQ@mail.gmail.com>
next in thread | previous in thread | raw e-mail | index | archive | help
On 03/08/2016 00:35, Zaphod Beeblebrox wrote: > I have just filed bug 211535. I'd like to be more helpful, but I'm having > some trouble with the level of optimization in the kernel. Much of kgdb's > output tells me that the value I'm looking for has been optimized away. > > So... how do I compile a kernel or a module without optimization I have this in my kernel configuration: makeoptions CONF_CFLAGS="-O1" Also I have to use amd64-gcc to build the kernel because of a problem that happens when using clang to compile amd64 kernel modules (particularly zfs) at that optimization level. It's as simple as: - pkg install amd64-xtoolchain-gcc - add CROSS_TOOLCHAIN=amd64-gcc to the buildkernel invocation > _and_ how > badly will that affect the runtime of a lightly loaded server? I think that nobody would be able to tell you that in advance. But I expect that you won't see any difference. Why don't you try and report back? :-) > My kernel is already compiled with -g. That tells me that I'm looking in > zap_leaf.c (part of ZFS). Can I simply compile zap_leaf.c without > optimization? -- Andriy Gapon
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?d3c8ec3b-9b91-9f79-c7cf-ad1f6660a3bf>