On Wed, 2019-01-09 at 10:52 +0000, Jerin Jacob Kollanukkaran wrote: > On Wed, 2019-01-09 at 10:19 +0000, Luca Boccassi wrote: > > On Wed, 2019-01-09 at 10:09 +0000, Jerin Jacob Kollanukkaran wrote: > > > On Wed, 2019-01-09 at 01:39 -0800, Yongseok Koh wrote: > > > > --------------------------------------------------------------- > > > > ---- > > > > --- > > > > In config/arm64_armv8_linuxapp_gcc, maximum available cache > > > > line > > > > size > > > > (128B) in arm64 implementations is set by default for generic > > > > config. > > > > However, setting 64B is preferable for meson build in order to > > > > support > > > > majority of CPUs which don't have Implementor ID or Part Number > > > > programmed > > > > on chip. > > > > > > Adding Luca to get input from distro build perspective. > > > > > > If I understand it correctly, distro build will be using > > > the generic config/arm/arm64_armv8_linuxapp_gcc for generic > > > build. > > > If so, We can not change cache line size for generic config > > > as mentined the reason are > > > https://mails.dpdk.org/archives/dev/2019-January/122441.html > > > > > > > > > I think, I way forward is to add > > > config/arm/arm64_a72_linuxapp_gcc > > > for meson. This config can be used for all SoC with A72 armv8 > > > implementation and may have sym link to specfific SoC to avoid > > > confusion to end users. > > > > For Meson, I recently sent a patch to use a common and stable > > baseline > > machine arg if the uses sets it to "default": > > > > https://patches.dpdk.org/patch/49477/ > > > > For distros, I think if, within that path, the cache size is set to > > the > > minimum common denominator like the -march is, it will be fine. > > > > At that point, what happens for "native" or otherwise specified > > builds > > it will not affect distros (as long as they use "default" like > > Debian > > and Ubuntu do). > > > > Thanks for the input > > > Does this answer your question? > > > Kind of.. Will you be building "the generic image" on ANY arm64 > machine > with following command? > > meson configure -Dmachine=default > meson build > cd build > ninja > ninja install > > If so, This patch will change the cache line size of generic build. > Right?
Yes, that's the command used everywhere on Debian/Ubuntu, regardless of the machine type, and this patch will change the value for those cases as far as I can see. Please bear in mind that I know really little about arm, so I am not sure which should be the default for maximum compatibility. -- Kind regards, Luca Boccassi
