[FFmpeg-devel] [PATCH] Remove mmx.h from dsputil_mmx.c
Michael Niedermayer
michaelni
Sat Mar 14 06:05:30 CET 2009
On Fri, Mar 13, 2009 at 08:38:09PM -0400, Alex Converse wrote:
> On Wed, Mar 11, 2009 at 3:44 PM, Michael Niedermayer <michaelni at gmx.at> wrote:
> > On Wed, Mar 11, 2009 at 03:19:03AM -0400, Alex Converse wrote:
> >> On Tue, Mar 10, 2009 at 10:04 PM, Michael Niedermayer <michaelni at gmx.at> wrote:
> >> > On Tue, Mar 10, 2009 at 09:19:56PM -0400, Alex Converse wrote:
> >> >> This is my first mmx patch so please bear with me.
> >> >
> >> >> diff --git a/libavcodec/x86/dsputil_mmx.c b/libavcodec/x86/dsputil_mmx.c
> >> >> index 2f47f5f..3771c5f 100644
> >> >> --- a/libavcodec/x86/dsputil_mmx.c
> >> >> +++ b/libavcodec/x86/dsputil_mmx.c
> >> >> @@ -28,7 +28,6 @@
> >> >> ?#include "libavcodec/mpegvideo.h"
> >> >> ?#include "libavcodec/simple_idct.h"
> >> >> ?#include "dsputil_mmx.h"
> >> >> -#include "mmx.h"
> >> >> ?#include "vp3dsp_mmx.h"
> >> >> ?#include "vp3dsp_sse2.h"
> >> >> ?#include "vp6dsp_mmx.h"
> >> >> @@ -278,16 +277,33 @@ static DECLARE_ALIGNED_8(const unsigned char, vector128[8]) =
> >> >>
> >> >> ?void put_signed_pixels_clamped_mmx(const DCTELEM *block, uint8_t *pixels, int line_size)
> >> >> ?{
> >> >> + ? ?const DCTELEM *p = block;
> >> >> + ? ?uint8_t *pix = pixels;
> >> >> ? ? ?int i;
> >> >>
> >> >> - ? ?movq_m2r(*vector128, mm1);
> >> >> - ? ?for (i = 0; i < 8; i++) {
> >> >> - ? ? ? ?movq_m2r(*(block), mm0);
> >> >> - ? ? ? ?packsswb_m2r(*(block + 4), mm0);
> >> >> - ? ? ? ?block += 8;
> >> >> - ? ? ? ?paddb_r2r(mm1, mm0);
> >> >> - ? ? ? ?movq_r2m(mm0, *pixels);
> >> >> - ? ? ? ?pixels += line_size;
> >> >> + ? ?__asm__ volatile ("movq %0, %%mm0" : : "m" (*vector128));
> >> >> + ? ?for (i = 0; i < 8; i+=4) {
> >> >> + ? ? ? ?__asm__ volatile (
> >> >> + ? ? ? ? ? ? ? ?"movq ? (%1), %%mm1 ? ? ? ? ? ? \n\t"
> >> >> + ? ? ? ? ? ? ? ?"movq 16(%1), %%mm2 ? ? ? ? ? ? \n\t"
> >> >> + ? ? ? ? ? ? ? ?"movq 32(%1), %%mm3 ? ? ? ? ? ? \n\t"
> >> >> + ? ? ? ? ? ? ? ?"movq 48(%1), %%mm4 ? ? ? ? ? ? \n\t"
> >> >> + ? ? ? ? ? ? ? ?"packsswb ?8(%1), %%mm1 ? ? ? ? \n\t"
> >> >> + ? ? ? ? ? ? ? ?"packsswb 24(%1), %%mm2 ? ? ? ? \n\t"
> >> >> + ? ? ? ? ? ? ? ?"packsswb 40(%1), %%mm3 ? ? ? ? \n\t"
> >> >> + ? ? ? ? ? ? ? ?"packsswb 56(%1), %%mm4 ? ? ? ? \n\t"
> >> >> + ? ? ? ? ? ? ? ?"paddb %%mm0, %%mm1 ? ? ? ? ? ? \n\t"
> >> >> + ? ? ? ? ? ? ? ?"paddb %%mm0, %%mm2 ? ? ? ? ? ? \n\t"
> >> >> + ? ? ? ? ? ? ? ?"paddb %%mm0, %%mm3 ? ? ? ? ? ? \n\t"
> >> >> + ? ? ? ? ? ? ? ?"paddb %%mm0, %%mm4 ? ? ? ? ? ? \n\t"
> >> >> + ? ? ? ? ? ? ? ?"movq %%mm1, (%0) ? ? ? ? ? ? ? \n\t"
> >> >> + ? ? ? ? ? ? ? ?"movq %%mm2, (%0, %2) ? ? ? ? ? \n\t"
> >> >> + ? ? ? ? ? ? ? ?"movq %%mm3, (%0, %2, 2) ? ? ? ?\n\t"
> >> >> + ? ? ? ? ? ? ? ?"movq %%mm4, (%0, %3) ? ? ? ? ? \n\t"
> >> >> + ? ? ? ? ? ? ? ?::"r" (pix), "r" (p), "r"((x86_reg)line_size), "r"((x86_reg)3*line_size)
> >> >> + ? ? ? ? ? ? ? ?:"memory");
> >> >> + ? ? ? ?p += 32;
> >> >> + ? ? ? ?pix += 4*line_size;
> >> >
> >> > 1. the for() should not be there, it should be in the asm()
> >>
> >> The for loop has been eliminated
> >>
> >> > 2. benchmark is always needed when messing with optimized code.
> >> > ? ?START/STOP_TIMER around the point that calls the changed
> >> > ? ?function is likely the easiest way to do it
> >>
> >> The benchmarks seem inconclusive. The unpatched version seems to start
> >> out faster and end slower. I don't know what of make of this.
> >
> > [...]
> >
> >> diff --git a/libavcodec/x86/dsputil_mmx.c b/libavcodec/x86/dsputil_mmx.c
> >> index 2f47f5f..b9679ad 100644
> >> --- a/libavcodec/x86/dsputil_mmx.c
> >> +++ b/libavcodec/x86/dsputil_mmx.c
> >> @@ -28,7 +28,6 @@
> >> ?#include "libavcodec/mpegvideo.h"
> >> ?#include "libavcodec/simple_idct.h"
> >> ?#include "dsputil_mmx.h"
> >> -#include "mmx.h"
> >> ?#include "vp3dsp_mmx.h"
> >> ?#include "vp3dsp_sse2.h"
> >> ?#include "vp6dsp_mmx.h"
> >> @@ -276,19 +275,39 @@ void put_pixels_clamped_mmx(const DCTELEM *block, uint8_t *pixels, int line_size
> >> ?static DECLARE_ALIGNED_8(const unsigned char, vector128[8]) =
> >> ? ?{ 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80 };
> >>
> >> +#define put_signed_pixels_clamped_mmx_half \
> >> + ? ? ? ? ? ?"movq ? (%1), %%mm1 ? ? ? ? ? ? ? ? \n\t"\
> >> + ? ? ? ? ? ?"movq 16(%1), %%mm2 ? ? ? ? ? ? ? ? \n\t"\
> >> + ? ? ? ? ? ?"movq 32(%1), %%mm3 ? ? ? ? ? ? ? ? \n\t"\
> >> + ? ? ? ? ? ?"movq 48(%1), %%mm4 ? ? ? ? ? ? ? ? \n\t"\
> >> + ? ? ? ? ? ?"packsswb ?8(%1), %%mm1 ? ? ? ? ? ? \n\t"\
> >> + ? ? ? ? ? ?"packsswb 24(%1), %%mm2 ? ? ? ? ? ? \n\t"\
> >> + ? ? ? ? ? ?"packsswb 40(%1), %%mm3 ? ? ? ? ? ? \n\t"\
> >> + ? ? ? ? ? ?"packsswb 56(%1), %%mm4 ? ? ? ? ? ? \n\t"\
> >> + ? ? ? ? ? ?"paddb %%mm0, %%mm1 ? ? ? ? ? ? ? ? \n\t"\
> >> + ? ? ? ? ? ?"paddb %%mm0, %%mm2 ? ? ? ? ? ? ? ? \n\t"\
> >> + ? ? ? ? ? ?"paddb %%mm0, %%mm3 ? ? ? ? ? ? ? ? \n\t"\
> >> + ? ? ? ? ? ?"paddb %%mm0, %%mm4 ? ? ? ? ? ? ? ? \n\t"\
> >> + ? ? ? ? ? ?"movq %%mm1, (%0) ? ? ? ? ? ? ? ? ? \n\t"\
> >> + ? ? ? ? ? ?"movq %%mm2, (%0, %2) ? ? ? ? ? ? ? \n\t"\
> >> + ? ? ? ? ? ?"movq %%mm3, (%0, %2, 2) ? ? ? ? ? ?\n\t"\
> >> + ? ? ? ? ? ?"movq %%mm4, (%0, %3) ? ? ? ? ? ? ? \n\t"
> >> +
> >> ?void put_signed_pixels_clamped_mmx(const DCTELEM *block, uint8_t *pixels, int line_size)
> >> ?{
> >> - ? ?int i;
> >> -
> >> - ? ?movq_m2r(*vector128, mm1);
> >> - ? ?for (i = 0; i < 8; i++) {
> >> - ? ? ? ?movq_m2r(*(block), mm0);
> >> - ? ? ? ?packsswb_m2r(*(block + 4), mm0);
> >> - ? ? ? ?block += 8;
> >> - ? ? ? ?paddb_r2r(mm1, mm0);
> >> - ? ? ? ?movq_r2m(mm0, *pixels);
> >> - ? ? ? ?pixels += line_size;
> >> - ? ?}
> >> + ? ?const DCTELEM *p = block;
> >> + ? ?uint8_t *pix = pixels;
> >> + ? ?x86_reg line_skip = line_size;
> >> +
> >> + ? ?__asm__ volatile (
> >> + ? ? ? ? ? ?"movq (%3), %%mm0 ? ? ? ? ? ? ? ? ? \n\t"
> >> + ? ? ? ? ? ?"lea (%2, %2, 2), %3 ? ? ? ? ? ? ? ?\n\t"
> >> + ? ? ? ? ? ?put_signed_pixels_clamped_mmx_half
> >> + ? ? ? ? ? ?"add $64, %1 ? ? ? ? ? ? ? ? ? ? ? ?\n\t"
> >> + ? ? ? ? ? ?"lea (%0, %2, 4), %0 ? ? ? ? ? ? ? ?\n\t"
> >> + ? ? ? ? ? ?put_signed_pixels_clamped_mmx_half
> >> + ? ? ? ? ? ?::"r" (pix), "r" (p), "r"(line_skip), "r" (vector128)
> >> + ? ? ? ? ? ?:"memory");
> >
> > you dont need the add $64, this can be done by changing the offsets
> > also %0,%1 and %3 are marked as input, while you change them
> >
>
> Fixed
>
> Do the x87 stack or the mm* registers need to be marked as clobbered?
strictly yes but we dont do it because it works and it might be faster
>
> Here is cycle estimation from Valgrind. I find it easier to read:
> Ir Dr Dw I1mr D1mr D1mw I2mr D2mr D2mw
> function put_signed_pixels_clamped_mmx:
> before:
> 16,088,784 6,033,294 2,681,464 122,988 34,505 259,448 991 292 27,624
> Cycle Estimation = Ir + 10*L1m + 100*L2m = 23,184,894
> after:
> 12,736,954 6,033,294 2,681,464 64,595 33,784 258,686 617 294 27,622
> Cycle Estimation = Ir + 10*L1m + 100*L2m = 19,160,904
nothing against valgrind but i prefer benchmarks done on real hardware
where its possible because we have more users that run ffmpeg on real
hw than who run it in emulators
[...]
--
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
Its not that you shouldnt use gotos but rather that you should write
readable code and code with gotos often but not always is less readable
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