Hi Carlo, On 15.03.2018 16:36, Carlo Pisani wrote: > I am experiencing a very annoying behavior with my HPPA C3600: if I > compile the (linux) kernel with -mlong-calls then the IO (e.g. file > copy) becomes very slow, and the PCI becomes unstable (i.e. it crashes > the machine) > > kernel gcc binutils with mlong without mlong > 4.15.7 4.9.3 2.25.1 13.4 MB/s 27.0 MB/s > 4.15.7 6.4.0 2.25.1 13.4 MB/s 27.0 MB/s > 4.15.7 6.4.0 2.29.1 14.4 MB/s 25.0 MB/s Interesting bad results! > these tests were performed with > > dd if=/dev/zero of=here bs=1k count=100000 > > -mlong-calls is enabled in the kernel by "CONFIG_MLONGCALLS" I think nobody else noticed the bad performance due to CONFIG_MLONGCALLS yet. I've now started some testing if we can disable that option on the debian kernels... > the help-guide says "If you configure the kernel to include many > drivers built-in instead as modules, the kernel executable may become > too big, so that the linker will not be able to resolve some long > branches and fails to link your vmlinux kernel. In that case enabling > this option will help you to overcome this limit by using the > -mlong-calls compiler option. Usually you want to say N here, unless > you e.g. want to build a kernel which includes all necessary drivers > built-in and which can be used for TFTP booting without the need to > have an initrd ramdisk. Enabling this option will probably slow down > your kernel" > > I need -mlong-calls because I need to compile the kernel without > kernel-modules Why? > all built-in, that makes the size of the kernel of > about 23Mbytes, thus without -mlong-calls the linker fails to "link" > objects > > let me know I'm not sure what kind of help you expect here? The only option I see is that you try to disable some options (modules) you won't need and thus reduce the kernel size. xfs, ipv6 and such are good candidates. Or use a 32bit kernel ? Helge -- To unsubscribe from this list: send the line "unsubscribe linux-parisc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
