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kbuild 2.5 v2.0 was released today by Keith Owens. One major improvement in this new version is a 30% speed increase over kbuild 2.4 by replacing a text-file read at each compile step with a memory mapped database (mdbm from BitKeeper). Regarding the speed gain, Keith says, "Now the nay-sayers will have to find something else to complain about!". He also warns, "... You know what they say about .0 releases ... User beware."
Currently this version is only available for i386 architectures. However, Keith adds, "Patches for other architectures and kernels will be out in the next few days, it takes time to generate and test patches for multiple architectures against different kernel trees."
From: Keith Owens
Cc: linux-kernel-mailing-list
Subject: Announce: Kernel Build for 2.5, Release 2.0 is available
Date: Fri, 05 Apr 2002 21:26:08 +1000
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Release 2.0 of kernel build for kernel 2.5 (kbuild 2.5) is available.
http://sourceforge.net/projects/kbuild/, Package kbuild-2.5, download
release 2.0.
... You know what they say about .0 releases ... User beware.
This announcement is for the base kbuild 2.5 code, i386 against 2.4.16.
It uses 2.4.16 because that gives a useful comparison against the
previous release and a decent branch point from kernel 2.4 to 2.5.
Patches for other architectures and kernels will be out in the next few
days, it takes time to generate and test patches for multiple
architectures against different kernel trees.
http://marc.theaimsgroup.com/?l=linux-kernel&m=99725412902968&w=2
contains information about the base release of kbuild 2.5.
Changelog:
New, faster core code, thanks to Larry McVoy for providing the
memory mapped database code.
Patches are now split into core (kernel independent), common
(architecture independent but kernel dependent) and arch
(architecture and kernel dependent) files. The core patch applies
to all kernels, both 2.4 and 2.5. The common and arch files apply
to specific kernels and hardware.
Other than being split into separate patches, kbuild 2.5 for the common
and i386 directories is almost unchanged from release 1.12. Tom
Duffy's patch for drivers/sbus/{audio,char}/Makefile.in has been
included. There are some minor changes where the more rigorous error
checking of this release found errors in kbuild 2.4 Makefiles.
The real change is the complete rewrite of the core code. Instead of
using a text file that is read by every compile step (slow!), kbuild
2.5 uses Larry McVoy's memory mapped database from BitKeeper (mdbm is
both GPL and BKL).
Full 2.4.16 .config, everything that compiles built in. 4 x Pentium
III (Cascades) @700MHz, 5600 Bogomips, 1Gb RAM, SCSI, 2.4.17-xfs.
kbuild 2.4:
make oldconfig 0:07
make dep 0:37 (make -j dep is unsafe on some architectures)
make -j8 bzImage modules 14:16
Total 15:00
make -j8 bzImage modules 2:10 (second run, no changes, spurious rebuilds)
kbuild 2.5:
make -j8 oldconfig installable 8:51 (no make dep needed :)
make -j8 oldconfig installable :14 (second run, no changes)
More accurate kernel build, easier to write and understand Makefiles,
30% faster than kbuild 2.4. Now the nay-sayers will have to find
something else to complain about!
I have not tried this release of kbuild 2.5 with a recent version of
CML2. It used to work on CML2 1.9.15, but probably needs some work for
the latest CML2. Note that kbuild 2.5 and CML2 are independent, each
can function without the other, complaints about CML2 have nothing to
do with kbuild 2.5.
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On Fri, 05 Apr 2002 21:26:08 +1000,
Keith Owens wrote:
>kbuild 2.4:
> make oldconfig 0:07
> make dep 0:37 (make -j dep is unsafe on some architectures)
> make -j8 bzImage modules 14:16
> Total 15:00
> make -j8 bzImage modules 2:10 (second run, no changes, spurious rebuilds)
>
>kbuild 2.5:
> make -j8 oldconfig installable 8:51 (no make dep needed :)
> make -j8 oldconfig installable :14 (second run, no changes)
Just to avoid any confusion. kbuild 2.4 is the existing kernel build
system, as used in Marcelo's and Linus's kernels. kbuild 2.5 is the
complete rewrite of the kernel build system. Although it says 2.5,
kbuild 2.5 will run on 2.4 kernels, it was developed on 2.4.
The timings above were for exactly the same .config on the same build
machine, building a 2.4.16 kernel, using the existing and new kernel
build system. Compared to the existing build system, kbuild 2.5 is
much more robust (I found several bugs in the 2.4 rules while
developing kbuild 2.5), provides more facilities, has debugging
information, is more accurate (2.5 tracks everything, 2.4 only managed
about 80% tracking accuracy) and still manages to run 30% faster than
the existing build system.
Although kbuild 2.5 will run on 2.4 kernels, I have no plans to send
all of kbuild 2.5 to Marcelo. Changing the kernel build on a stable
kernel is a bad idea. I will be sending some kbuild 2.4 bug fixes to
Marcelo but not the rest of kbuild 2.5. I am now working on kbuild 2.5
patches for 2.4.18, 2.4.19-pre6, 2.5.7 and 2.5.8-pre1 as well as for
other architectures, see http://sourceforge.net/projects/kbuild for
updates.
