| Message ID | 20150527001113.2506.23159.stgit@bahia.huguette.org (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
Greg Kurz <gkurz@linux.vnet.ibm.com> writes: > 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. > > Signed-off-by: Greg Kurz <gkurz@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 * + Why did you drop "char-width screen-depth * -" in the new code? This is not me mentioned in the description. Regards Nikunj
On Wed, 27 May 2015 02:11:13 +0200 Greg Kurz <gkurz@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! > Signed-off-by: Greg Kurz <gkurz@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. 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). Thomas
On Wed, 27 May 2015 10:41:06 +0530 Nikunj A Dadhania <nikunj@linux.vnet.ibm.com> wrote: > Greg Kurz <gkurz@linux.vnet.ibm.com> writes: > > > 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. > > > > Signed-off-by: Greg Kurz <gkurz@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 * + > > Why did you drop "char-width screen-depth * -" in the new code? This is > not me mentioned in the description. > This is because the current inner loop increments the address. When the loop ends, we're pointing at the next char, that is char-width * screen-depth bytes too far. In the new code, the address is duped on the stack before calling hv-logical-memop, so we don't need to fix it when proceeding to next line. In my first attempt, I forgot to drop the subtraction and got an interesting visual result :) > Regards > Nikunj Cheers. -- Greg
Greg Kurz <gkurz@linux.vnet.ibm.com> writes: > On Wed, 27 May 2015 10:41:06 +0530 > Nikunj A Dadhania <nikunj@linux.vnet.ibm.com> wrote: > >> Greg Kurz <gkurz@linux.vnet.ibm.com> writes: >> >> > 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. >> > >> > Signed-off-by: Greg Kurz <gkurz@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 * + >> >> Why did you drop "char-width screen-depth * -" in the new code? This is >> not me mentioned in the description. >> > > This is because the current inner loop increments the address. When the loop > ends, we're pointing at the next char, that is char-width * screen-depth bytes > too far. > > In the new code, the address is duped on the stack before calling hv-logical-memop, > so we don't need to fix it when proceeding to next line. Ah ok, i missed that 1+ in the loop. > In my first attempt, I forgot to drop the subtraction and got an interesting > visual result :) Regards Nikunj
On Wed, 27 May 2015 07:59:34 +0200 Thomas Huth <thuth@redhat.com> wrote: > On Wed, 27 May 2015 02:11:13 +0200 > Greg Kurz <gkurz@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 <gkurz@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
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 ;
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. Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com> --- slof/fs/fbuffer.fs | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)