Re: can linaro toolchain compile ARM earlier than Cortex A8?
On 24/03/11 03:09, Michael Hope wrote: Hi Barry. GCC can be switched at runtime by supplying -march=* and/or -mcpu=* flags to the compiler, just as you have done below. The '--with-arch=*' lines you see below set what GCC compiles to by default. While that is true, but the libraries that come with the compiler are probably still inappropriate for older architectures. The short answer is that, no, the Linaro *binary* releases will not support -march=armv5. However, you can build your own compiler from the Linaro sources, and then build the libraries you need to match, and you can have v5 support. This is not a straightforward process. :( If you'd prefer not to build your own tools, may I recommend CodeSourcery's Sourcery G++ Lite for ARM GNU/Linux: http://www.codesourcery.com/sgpp/lite/arm That compiler defaults to ARMv5TE. If that's too new, the toolchain also contains prebuilt libraries for ARMv4T (-march=armv4t) and those should be compatible. Although it is not the Linaro compiler, it is somewhat similar, and programs you build should be compatible with Ubuntu. (Disclosure: I work for CodeSourcery). Hope that helps Andrew ___ linaro-toolchain mailing list linaro-toolchain@lists.linaro.org http://lists.linaro.org/mailman/listinfo/linaro-toolchain
Re: can linaro toolchain compile ARM earlier than Cortex A8?
On Thu, 24 Mar 2011 11:36:17 +0100, Andrew Stubbs wrote: The short answer is that, no, the Linaro *binary* releases will not support -march=armv5. However, you can build your own compiler from the Linaro sources, and then build the libraries you need to match, and you can have v5 support. This is not a straightforward process. :( You can always use the OpenWrt buildroot to easily build a custom Linaro-based crosscompiler, just make sure you select the right libc for your needs (we use uClibc by default) and a target similar to yours. Imre ___ linaro-toolchain mailing list linaro-toolchain@lists.linaro.org http://lists.linaro.org/mailman/listinfo/linaro-toolchain
Re: can linaro toolchain compile ARM earlier than Cortex A8?
On 24/03/11 11:05, Imre Kaloz wrote: On Thu, 24 Mar 2011 11:36:17 +0100, Andrew Stubbs wrote: However, you can build your own compiler from the Linaro sources, and then build the libraries you need to match, and you can have v5 support. This is not a straightforward process. :( You can always use the OpenWrt buildroot to easily build a custom Linaro-based crosscompiler, just make sure you select the right libc for your needs (we use uClibc by default) and a target similar to yours. Or OpenEmbedded or CrossTool / CrossTool-NG. Andrew ___ linaro-toolchain mailing list linaro-toolchain@lists.linaro.org http://lists.linaro.org/mailman/listinfo/linaro-toolchain
[ACTIVITY] March 22-24
Hi, * resubmitted and committed store sink patch to trunk, I'll commit it to gcc-linaro-4.6 next week * submitted autodetection of vector size patch to gcc-patches, I'l commit it next week * started testing a patch that makes mvectorize-with-neon-quad the default * DenBench: found some more cases where vectorization of strided accesses using vzip/vuzp causes degradation. Since Richard is making a lot of progress with vlsd/vst, I think it doesn't make sense to spend too much time on vzip/vuzp, and I am going to run DenBench without this patch. Ira ___ linaro-toolchain mailing list linaro-toolchain@lists.linaro.org http://lists.linaro.org/mailman/listinfo/linaro-toolchain
Re: can linaro toolchain compile ARM earlier than Cortex A8?
2011/3/24 Andrew Stubbs > > On 24/03/11 11:05, Imre Kaloz wrote: >> >> On Thu, 24 Mar 2011 11:36:17 +0100, Andrew Stubbs >> wrote: >>> >>> However, you can build your own compiler from the Linaro sources, and >>> then build the libraries you need to match, and you can have v5 support. >>> This is not a straightforward process. :( >> >> You can always use the OpenWrt buildroot to easily build a custom >> Linaro-based crosscompiler, just make sure you select the right libc for >> your needs (we use uClibc by default) and a target similar to yours. > > Or OpenEmbedded or CrossTool / CrossTool-NG. Thank all of you! you really help me much! You toolchain team is really great! In fact, i knew how to compile a toolchain. As i said, i have compiled a toolchain by simple options: Configured with: ../gcc-linaro-4.4-2011.02-0/ configure --target=arm-none-linux-gnueabi --prefix=/home/vmuser/development/toolchain/build-toolchain/tools --enable-languages=c,c++ --disable-libgomp Thread model: posix gcc version 4.4.5 (Linaro GCC 4.4-2011.02-0) it can make uboot work with arch=armv5. i want to know whether any performance is lost by my simple configure options if the toolchain is used to armv7 with vfpv3? GCC documents show that those options we use to compile gcc will become the default options of gcc runtime. But what is the real benefit toolchains can get by configuring gcc with default arch and fpu since we can switch arch options at runtime? Is the key glibc? If compiling glibc by gcc with options for a special ARM arch and float point unit, it will improve the performance of glibc to the arch? And then the glibc will not support other arch or SoCs without the specified float point unit? > > Andrew > > ___ > linaro-toolchain mailing list > linaro-toolchain@lists.linaro.org > http://lists.linaro.org/mailman/listinfo/linaro-toolchain ___ linaro-toolchain mailing list linaro-toolchain@lists.linaro.org http://lists.linaro.org/mailman/listinfo/linaro-toolchain
[ACTIVITY] March 20-24
Hello, Implemented a patch to apply SMS in the presence of instructions with REG_INC_NOTE. (this occurs in telecom/autocor thus SMS needs to be run with -fno-auto-inc-dec flag to be applied) Sent a merge request to gcc-linaro for the SMS patches. Thanks to Andrew Stubbs for his help. https://code.launchpad.net/~eres/gcc-linaro/SMS_doloop_for_ARM I intend to send a request to gcc-linaro.4.6 as well. Thanks, Revital ___ linaro-toolchain mailing list linaro-toolchain@lists.linaro.org http://lists.linaro.org/mailman/listinfo/linaro-toolchain
Re: can linaro toolchain compile ARM earlier than Cortex A8?
On Fri, Mar 25, 2011 at 2:59 AM, Barry Song <21cn...@gmail.com> wrote: > 2011/3/24 Andrew Stubbs >> >> On 24/03/11 11:05, Imre Kaloz wrote: >>> >>> On Thu, 24 Mar 2011 11:36:17 +0100, Andrew Stubbs >>> wrote: However, you can build your own compiler from the Linaro sources, and then build the libraries you need to match, and you can have v5 support. This is not a straightforward process. :( >>> >>> You can always use the OpenWrt buildroot to easily build a custom >>> Linaro-based crosscompiler, just make sure you select the right libc for >>> your needs (we use uClibc by default) and a target similar to yours. >> >> Or OpenEmbedded or CrossTool / CrossTool-NG. > > Thank all of you! you really help me much! You toolchain team is really > great! > > In fact, i knew how to compile a toolchain. As i said, i have > compiled a toolchain by simple options: > Configured with: ../gcc-linaro-4.4-2011.02-0/ > configure > --target=arm-none-linux-gnueabi > --prefix=/home/vmuser/development/toolchain/build-toolchain/tools > --enable-languages=c,c++ --disable-libgomp > Thread model: posix > gcc version 4.4.5 (Linaro GCC 4.4-2011.02-0) > > it can make uboot work with arch=armv5. > > i want to know whether any performance is lost by my simple configure > options if the toolchain is used to armv7 with vfpv3? GCC documents > show that those options we use to compile gcc will become the default > options of gcc runtime. But what is the real benefit toolchains can > get by configuring gcc with default arch and fpu since we can switch > arch options at runtime? > > Is the key glibc? If compiling glibc by gcc with options for a special > ARM arch and float point unit, it will improve the performance of > glibc to the arch? And then the glibc will not support other arch or > SoCs without the specified float point unit? Hi Barry. The short answer is 'it depends' :) GCC is more than a compiler and includes other things such as a runtime library (libgcc) and hooks into the libc for features like thread local storage. These are built for the architecture and floating point unit options you pass to GCC's configure, so if you want one toolchain that runs everywhere then you need to configure it for the lowest common denominator (normally a ARMv5T in ARM mode with no FPU). A similar argument applies to GLIBC. The next question is, does this matter for your application? What workload will your product run and will it be meaningfully affected by this lowest common denominator build? * If your application uses a lot of floating point, then the lack of FPU support in GLIBC matters * If your product has limited memory, then the smaller code size of Thumb-2 is worthwhile * If you need to squeeze out another 5 % in performance, then using ARMv7 instead of ARMv5 will help There are other technical solutions such as: * Building libgcc and glibc for the different variants and picking the best at link time * Building them and picking at dynamic link time using hwcaps or similar These make sense for a generic binary toolchain such as the CodeSourcery one Andrew mentioned, and for generic distributions such as Ubuntu but not for a focused end user product. -- Michael ___ linaro-toolchain mailing list linaro-toolchain@lists.linaro.org http://lists.linaro.org/mailman/listinfo/linaro-toolchain
