On Wed, 27 May 2015 07:59:34 +0200 Thomas Huth <th...@redhat.com> wrote:
> On Wed, 27 May 2015 02:11:13 +0200 > Greg Kurz <gk...@linux.vnet.ibm.com> wrote: > > > SLOF currently calls hv-logical-load and hv-logical-store for every pixel > > when enabling or disabling the cursor. This is suboptimal when writing one > > char at a time to the console since terminal-write always toggles the > > cursor. > > And this is precisely what grub is doing when the user wants to edit a menu > > entry... the result is an incredibly slow and barely usable interface. > > > > The inner loop in fb8-toggle-cursor handles a contiguous region: it can be > > converted to hv-logical-memop. The result is 32 times less hcalls per char > > and a serious improvement in grub usability. > > Good idea for an optimization! > Heh no big deal... the hardest part was to find that the LOAD/STORE avalanche was coming from these rb@ and rb! words. SLOF is still a mysterious beast to me :) > > Signed-off-by: Greg Kurz <gk...@linux.vnet.ibm.com> > > --- > > slof/fs/fbuffer.fs | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/slof/fs/fbuffer.fs b/slof/fs/fbuffer.fs > > index 756f05a..46b59bf 100644 > > --- a/slof/fs/fbuffer.fs > > +++ b/slof/fs/fbuffer.fs > > @@ -99,8 +99,8 @@ CREATE bitmap-buffer 400 4 * allot > > : fb8-toggle-cursor ( -- ) > > line# fb8-line2addr column# fb8-columns2bytes + > > char-height 0 ?DO > > - char-width screen-depth * 0 ?DO dup dup rb@ -1 xor swap rb! 1+ > > LOOP > > - screen-width screen-depth * + char-width screen-depth * - > > + dup dup 0 char-width screen-depth * 1 hv-logical-memop drop > > + screen-width screen-depth * + > > LOOP drop > > ; > > If you use hv-logical-memop in this file here, you definitely break > board-js2x, since this is bare metal and hv-logical-memop is not > defined there. > Of course, this is common code... I'll remember for next time. :) > I think you should either move the new function to board-qemu and handle > it there like it is done for hcall-invert-screen already, or we could > think of introducing a helper function that is defined by each board > which does the xor operation on a memory region (that way we could > maybe also unify hcall-invert-screen and fb8-invert-screen again). > I guess the first proposal is the obvious fix. From there, we can work out a patchset for the second proposal. > Thomas > Cheers. -- Greg _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
