Date: Wed, 29 Mar 2017 15:53:16 +0000 From: Brooks Davis <brooks@freebsd.org> To: Mark Millard <markmi@dsl-only.net> Cc: Dimitry Andric <dim@FreeBSD.org>, FreeBSD Ports <freebsd-ports@freebsd.org>, FreeBSD PowerPC ML <freebsd-ppc@freebsd.org>, FreeBSD Toolchain <freebsd-toolchain@freebsd.org>, FreeBSD Current <freebsd-current@freebsd.org> Subject: Re: FYI: what it takes for RAM+swap to build devel/llvm40 with 4 processors or cores and WITH__DEBUG= (powerpc64 example) Message-ID: <20170329155316.GK59667@spindle.one-eyed-alien.net> In-Reply-To: <45E32F4F-A238-47AA-8E1E-7AD4D9E857D9@dsl-only.net> References: <3EDEF0B7-59C5-4648-9737-6682E18645BC@dsl-only.net> <39C60316-F905-490D-B0AB-BC24D7F351A2@dsl-only.net> <7F94CE59-D2CC-4D6F-B1CD-FF3D1F8EDCE7@FreeBSD.org> <45E32F4F-A238-47AA-8E1E-7AD4D9E857D9@dsl-only.net>
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--m1UC1K4AOz1Ywdkx Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Mar 27, 2017 at 03:25:04AM -0700, Mark Millard wrote: > On 2017-Mar-27, at 2:41 AM, Dimitry Andric <dim@FreeBSD.org> wrote: >=20 > > On 26 Mar 2017, at 23:36, Mark Millard <markmi@dsl-only.net> wrote: > >>=20 > >> I upgraded from llvm40 r4 to final. An interesting result was > >> its creation of a backup package for llvm40-4.0.0.r4: > >>=20 > >> about 13 cpu-core-hours running pkg create > >>=20 > >> (Remember: I've been building with WITH_DEBUG=3D ) Its > >> single-threaded status stands out via elapsed time > >> approximately matching. > >>=20 > >> I'll note that it was somewhat under 6 elapsed hours for > >> staging to have been populated (-j4 with 4 cores present > >> helps for this part). > >>=20 > >> (Of course these elapsed-time figures are rather system > >> dependent, although the ratio might be more stable.) > >>=20 > >>=20 > >>=20 > >> Also interesting was: > >>=20 > >> Installed packages to be REMOVED: > >> llvm40-4.0.0.r4 > >>=20 > >> Number of packages to be removed: 1 > >>=20 > >> The operation will free 49 GiB. > >=20 > > Yes, this is big. But there is no real need to build the llvm ports > > with debug information, unless you want to hack on llvm itself. And > > in that case, you are better served by a Subversion checkout or Git > > clone from upstream instead. > >=20 > > -Dimitry >=20 > FYI: >=20 > Historically unless something extreme like this ends up > involved I build everything using WITH_DEBUG=3D or explicit > -g's in order to have better information on any failure. >=20 > This is extreme enough that next time I synchronize > /usr/ports and it has a devel/llvm40 update I'll > likely rebuild devel/llvm40 without using WITH_DEBUG=3D . > I'm more concerned with the time it takes than with > the file system space involved. In the case of LLVM, enabling debug builds does a LOT more than adding symbols. It's much more like enabling WITNESS and INVARIANTS in your kernel, except that the performance of the resulting binary is much worse than a WITNESS kernel (more like 10x slowdown). As Dimitry points out, these builds are of questionable value in ports so garbage collecting the knob might be the sensable thing to do. -- Brooks --m1UC1K4AOz1Ywdkx Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEcBAEBAgAGBQJY29hrAAoJEKzQXbSebgfA6cgH/1FWA1dO2yctl/WJzfe4cF2E 1QRc3LUXX/DR9NktYS1GyLUJvgSncqNBMTBIwgeto5JxESn5A9fwry9L3koVCNFC GyjK+y1mNakVnZsFpe42QxKg53xv2Mi2ummNuatebC23a6ari++l/ioPIpR0tI+h nXRlH+PQYmXRnZvFoB2knVOXp5U++UkeoqJ0RnT17hHnwvLVwMlRdFyC+IoAuVZb xHb7bwm7yk0zo66onLfMcuj7MlIOgncg5l6KB42MTh6uIKY23LNl3qYernRbodnj 9t6eKI1mnD3nA10G8b0MBoUoDPb9/MkubIm4jRC1ag0k7Dj7YdHE8Wh/pLOyfxY= =MI2X -----END PGP SIGNATURE----- --m1UC1K4AOz1Ywdkx--
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