On 03/16/2017 10:57 PM, Dylan Baker wrote: > Quoting Ilia Mirkin (2017-03-16 14:32:09) >> On Thu, Mar 16, 2017 at 5:25 PM, Dylan Baker <dylan@xxxxxxxxxxxxx> wrote: >>> Why bother, and why would we want this? │~ >>> >>> First it's written in python, which means the potential developer base >>> is massive. And it provides a recursive view for humans, but a >>> non-recursive view for the system. This is the best of both worlds, >>> humans can organize the build system in a way that makes sense, and the >>> machine gets a non-recursive build system. It also uses ninja rather >>> than make, and ninja is faster than make inherently. Meson is also a >>> simpler syntax than autotools or cmake it's not Turing Complete by >>> design nor does it expose python, again, by design. This allows meson >>> itself to be reimplemented in a another language if python becomes a >>> dead-end or a bottle-neck. It also makes it much easier to understand >>> what the build system is doing. >>> >>> What's different about using meson? >>> >>> Well, apart from a faster builds and less magic in the build system? The >>> configure flags are different, it uses -D<opt>=<value> more like cmake >>> than the --enable or --with flags of autotools, although oddly it uses >>> --prefix and friends when calling meson, but not with mesonconf, there's >>> a bug opened on this. Meson also doesn't support in-tree builds at all; >>> all builds are done out of tree. It also doesn't provide a "make dist" >>> target, fortunately there's this awesome tool called git, and it >>> provides a "git archive" command that does much the same thing. Did I >>> mention it's fast? >>> >>> Here are the performance numbers I see on a 2 core 4 thread SKL, without >>> initial configuration, and building out of tree (using zsh): >>> >>> For meson the command line is: >>> time (meson build -Dmanpages=true && ninja -C build) >>> >>> For autotools the command line is: >>> time (mdkir build && cd build && ../autotools && make -j5 -l4)<Paste> >> >> Probably mkdir... > > derp, yeah. > >> >>> >>> meson (cold ccache): 13.37s user 1.74s system 255% cpu 5.907 total >>> autotools (cold ccache): 26.50s user 1.71s system 129% cpu 21.835 total >>> meson (hot ccache): 2.13s user 0.39s system 154% cpu 1.633 total >>> autotools (hot ccache): 13.93s user 0.73s system 102% cpu 14.259 total >>> >>> That's ~4x faster for a cold build and ~10x faster for a hot build. >>> >>> For a make clean && make style build with a hot cache: >>> meson: 4.64s user 0.33s system 334% cpu 1.486 total >>> autotools: 7.93s user 0.32s system 167% cpu 4.920 total >>> >>> Why bother with libdrm? >>> >>> It's a simple build system, that could be completely (or mostly >>> completely) be ported in a very short time, and could serve as a tech >>> demo for the advantages of using meson to garner feedback for embarking >>> on a larger project, like mesa (which is what I'm planning to work on >>> next). >>> >>> tl;dr >>> >>> I wrote this as practice for porting Mesa, and figured I might as well >>> send it out since I wrote it. >>> >>> It is very likely that neither of these large patches will show up on the >>> mailing list, but this is available at my github: >>> https://github.com/dcbaker/libdrm wip/meson >> >> I haven't looked at meson or your patches in detail, but autotools >> supports 2 very important use-cases very well: >> >> 1. ./configure --help >> 2. Cross-compilation with minimal requirement from the project being built >> >> Can you comment on how these are handled in meson? >> >> Cheers, >> >> -ilia > > 1. mesonconf <builddir> provides much the same thing. You can also read the > meson_options.txt file, which is generally pretty short. I haven't added > descriptions to the options in this patch. > > 2. you write a small ini style configuration file, something like: > [binaries] > c = '/usr/bin/aarch64-linux-gnu-gc' > ar = '/usr/bin/aarch64-linux-gnu-gcc-ar' > strip = '/usr/bin/aarch64-linux-gnu-strip' > pkg-config = '/usr/bin/aarch64-linux-gnu-pkgconfig' I'm sure meson is a good tool, but a simple : ./configure --target=arch64-linux-gnu is wayyyy simpler... And the only requirement is "sh" for autotools. Neil > > Then you just configure with: > meson build --cross-file cross_file.txt > > then just ninja like normal > > There's a more detailed walkthrough here: > https://github.com/mesonbuild/meson/wiki/Cross-compilation > > I was able to cross compile the arm libraries for aarch64 using basically the > above configuration (I had to write a wrapper script for pkg-config to set a > couple of environment variables and install and archlinux aarach64 chroot, > because arch), of course, I don't have access to any arm machines that I could > test with. > > Dylan > > > > _______________________________________________ > dri-devel mailing list > dri-devel@xxxxxxxxxxxxxxxxxxxxx > https://lists.freedesktop.org/mailman/listinfo/dri-devel >
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