* [FFmpeg-devel] [PATCH 1/2] lavu/riscv: assembler macros for VTYPE fields
@ 2024-05-14 19:35 Rémi Denis-Courmont
2024-05-14 19:35 ` [FFmpeg-devel] [PATCH 2/2] lavc/flacdsp: optimise RVV vector type for lpc16 Rémi Denis-Courmont
0 siblings, 1 reply; 3+ messages in thread
From: Rémi Denis-Courmont @ 2024-05-14 19:35 UTC (permalink / raw)
To: ffmpeg-devel
---
libavutil/riscv/asm.S | 48 +++++++++++++++++++++++++++++--------------
1 file changed, 33 insertions(+), 15 deletions(-)
diff --git a/libavutil/riscv/asm.S b/libavutil/riscv/asm.S
index 14be5055f5..ecf3081e61 100644
--- a/libavutil/riscv/asm.S
+++ b/libavutil/riscv/asm.S
@@ -96,20 +96,38 @@
.endm
#endif
+#define VTYPE_E8 000
+#define VTYPE_E16 010
+#define VTYPE_E32 020
+#define VTYPE_E64 030
+
+#define VTYPE_MF8 05
+#define VTYPE_MF4 06
+#define VTYPE_MF2 07
+#define VTYPE_M1 00
+#define VTYPE_M2 01
+#define VTYPE_M4 02
+#define VTYPE_M8 03
+
+#define VTYPE_TU 0000
+#define VTYPE_TA 0100
+#define VTYPE_MU 0000
+#define VTYPE_MA 0200
+
/* Convenience macro to load a Vector type (vtype) as immediate */
.macro lvtypei rd, e, m=m1, tp=tu, mp=mu
.ifc \e,e8
- .equ ei, 0
+ .equ ei, VTYPE_E8
.else
.ifc \e,e16
- .equ ei, 8
+ .equ ei, VTYPE_E16
.else
.ifc \e,e32
- .equ ei, 16
+ .equ ei, VTYPE_E32
.else
.ifc \e,e64
- .equ ei, 24
+ .equ ei, VTYPE_E64
.else
.error "Unknown element type"
.endif
@@ -118,25 +136,25 @@
.endif
.ifc \m,m1
- .equ mi, 0
+ .equ mi, VTYPE_M1
.else
.ifc \m,m2
- .equ mi, 1
+ .equ mi, VTYPE_M2
.else
.ifc \m,m4
- .equ mi, 2
+ .equ mi, VTYPE_M4
.else
.ifc \m,m8
- .equ mi, 3
+ .equ mi, VTYPE_M8
.else
.ifc \m,mf8
- .equ mi, 5
+ .equ mi, VTYPE_MF8
.else
.ifc \m,mf4
- .equ mi, 6
+ .equ mi, VTYPE_MF4
.else
.ifc \m,mf2
- .equ mi, 7
+ .equ mi, VTYPE_MF2
.else
.error "Unknown multiplier"
.equ mi, 3
@@ -149,20 +167,20 @@
.endif
.ifc \tp,tu
- .equ tpi, 0
+ .equ tpi, VTYPE_TU
.else
.ifc \tp,ta
- .equ tpi, 64
+ .equ tpi, VTYPE_TA
.else
.error "Unknown tail policy"
.endif
.endif
.ifc \mp,mu
- .equ mpi, 0
+ .equ mpi, VTYPE_MU
.else
.ifc \mp,ma
- .equ mpi, 128
+ .equ mpi, VTYPE_MA
.else
.error "Unknown mask policy"
.endif
--
2.43.0
_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
To unsubscribe, visit link above, or email
ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
^ permalink raw reply [flat|nested] 3+ messages in thread* [FFmpeg-devel] [PATCH 2/2] lavc/flacdsp: optimise RVV vector type for lpc16
2024-05-14 19:35 [FFmpeg-devel] [PATCH 1/2] lavu/riscv: assembler macros for VTYPE fields Rémi Denis-Courmont
@ 2024-05-14 19:35 ` Rémi Denis-Courmont
2024-05-14 19:42 ` Rémi Denis-Courmont
0 siblings, 1 reply; 3+ messages in thread
From: Rémi Denis-Courmont @ 2024-05-14 19:35 UTC (permalink / raw)
To: ffmpeg-devel
This calculates the optimal vector type value at run-time based on the
hardware vector length and the FLAC LPC prediction order. In this
particular case, the additional computation is easily amortised over
the loop iterations:
T-Head C908: C V before V after
flac_lpc_16_13: 14180.2 11229.0 7338.5
flac_lpc_16_16: 16833.2 11091.0 7248.5
flac_lpc_16_29: 28817.2 11455.7 10506.5
flac_lpc_16_32: 31059.7 10368.5 11305.2
With 128-bit vectors, improvements are expected for the first two
test cases only. For the other two, there is overhead but below noise.
Improvements should be better observable with prediction order of 8
and less, or on hardware with larger vector sizes.
The same optimisation strategy should be applicable to LPC32
(and work-in-progress LPC33), but is left as a future exercise.
---
libavcodec/riscv/flacdsp_init.c | 2 +-
libavcodec/riscv/flacdsp_rvv.S | 10 ++++++++--
2 files changed, 9 insertions(+), 3 deletions(-)
diff --git a/libavcodec/riscv/flacdsp_init.c b/libavcodec/riscv/flacdsp_init.c
index 77ffd09244..097f938f04 100644
--- a/libavcodec/riscv/flacdsp_init.c
+++ b/libavcodec/riscv/flacdsp_init.c
@@ -71,7 +71,7 @@ av_cold void ff_flacdsp_init_riscv(FLACDSPContext *c, enum AVSampleFormat fmt,
if ((flags & AV_CPU_FLAG_RVV_I32) && (flags & AV_CPU_FLAG_RVB_ADDR)) {
int vlenb = ff_get_rv_vlenb();
- if (vlenb >= 16)
+ if ((flags & AV_CPU_FLAG_RVB_BASIC) && vlenb >= 16)
c->lpc16 = ff_flac_lpc16_rvv;
c->wasted32 = ff_flac_wasted32_rvv;
diff --git a/libavcodec/riscv/flacdsp_rvv.S b/libavcodec/riscv/flacdsp_rvv.S
index 8b9c626198..42cece9786 100644
--- a/libavcodec/riscv/flacdsp_rvv.S
+++ b/libavcodec/riscv/flacdsp_rvv.S
@@ -20,8 +20,14 @@
#include "libavutil/riscv/asm.S"
-func ff_flac_lpc16_rvv, zve32x
- vsetvli zero, a2, e32, m8, ta, ma
+func ff_flac_lpc16_rvv, zve32x, zbb
+ csrr t0, vlenb
+ addi t2, a2, -1
+ clz t0, t0
+ clz t2, t2
+ addi t0, t0, VTYPE_E32 | VTYPE_M8 | VTYPE_TA | VTYPE_MA
+ sub t0, t0, t2 // t0 += log2(next_power_of_two(len) / vlenb) - 1
+ vsetvl zero, a2, t0
vle32.v v8, (a1)
sub a4, a4, a2
vle32.v v16, (a0)
--
2.43.0
_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
To unsubscribe, visit link above, or email
ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [FFmpeg-devel] [PATCH 2/2] lavc/flacdsp: optimise RVV vector type for lpc16
2024-05-14 19:35 ` [FFmpeg-devel] [PATCH 2/2] lavc/flacdsp: optimise RVV vector type for lpc16 Rémi Denis-Courmont
@ 2024-05-14 19:42 ` Rémi Denis-Courmont
0 siblings, 0 replies; 3+ messages in thread
From: Rémi Denis-Courmont @ 2024-05-14 19:42 UTC (permalink / raw)
To: ffmpeg-devel
Le tiistaina 14. toukokuuta 2024, 22.35.57 EEST Rémi Denis-Courmont a écrit :
> This calculates the optimal vector type value at run-time based on the
> hardware vector length and the FLAC LPC prediction order. In this
> particular case, the additional computation is easily amortised over
> the loop iterations:
>
> T-Head C908: C V before V after
> flac_lpc_16_13: 14180.2 11229.0 7338.5
> flac_lpc_16_16: 16833.2 11091.0 7248.5
> flac_lpc_16_29: 28817.2 11455.7 10506.5
> flac_lpc_16_32: 31059.7 10368.5 11305.2
>
> With 128-bit vectors, improvements are expected for the first two
> test cases only. For the other two, there is overhead but below noise.
> Improvements should be better observable with prediction order of 8
> and less, or on hardware with larger vector sizes.
>
> The same optimisation strategy should be applicable to LPC32
> (and work-in-progress LPC33), but is left as a future exercise.
> ---
> libavcodec/riscv/flacdsp_init.c | 2 +-
> libavcodec/riscv/flacdsp_rvv.S | 10 ++++++++--
> 2 files changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/libavcodec/riscv/flacdsp_init.c
> b/libavcodec/riscv/flacdsp_init.c index 77ffd09244..097f938f04 100644
> --- a/libavcodec/riscv/flacdsp_init.c
> +++ b/libavcodec/riscv/flacdsp_init.c
> @@ -71,7 +71,7 @@ av_cold void ff_flacdsp_init_riscv(FLACDSPContext *c, enum
> AVSampleFormat fmt, if ((flags & AV_CPU_FLAG_RVV_I32) && (flags &
> AV_CPU_FLAG_RVB_ADDR)) { int vlenb = ff_get_rv_vlenb();
>
> - if (vlenb >= 16)
> + if ((flags & AV_CPU_FLAG_RVB_BASIC) && vlenb >= 16)
> c->lpc16 = ff_flac_lpc16_rvv;
>
> c->wasted32 = ff_flac_wasted32_rvv;
> diff --git a/libavcodec/riscv/flacdsp_rvv.S b/libavcodec/riscv/flacdsp_rvv.S
> index 8b9c626198..42cece9786 100644
> --- a/libavcodec/riscv/flacdsp_rvv.S
> +++ b/libavcodec/riscv/flacdsp_rvv.S
> @@ -20,8 +20,14 @@
>
> #include "libavutil/riscv/asm.S"
>
> -func ff_flac_lpc16_rvv, zve32x
> - vsetvli zero, a2, e32, m8, ta, ma
> +func ff_flac_lpc16_rvv, zve32x, zbb
> + csrr t0, vlenb
> + addi t2, a2, -1
> + clz t0, t0
> + clz t2, t2
> + addi t0, t0, VTYPE_E32 | VTYPE_M8 | VTYPE_TA | VTYPE_MA
> + sub t0, t0, t2 // t0 += log2(next_power_of_two(len) / vlenb) -
> 1
Ok so checkasm can't sense it since we don't test that,
but I guess that this might crash due to illegal vector configuration if
- pred_order <= 2 with 128-bit vectors,
- pred_order <= 4 with 256-bit vectors,
- and so on.
This needs a little bit more work.
> + vsetvl zero, a2, t0
> vle32.v v8, (a1)
> sub a4, a4, a2
> vle32.v v16, (a0)
--
Rémi Denis-Courmont
http://www.remlab.net/
_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
To unsubscribe, visit link above, or email
ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2024-05-14 19:42 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2024-05-14 19:35 [FFmpeg-devel] [PATCH 1/2] lavu/riscv: assembler macros for VTYPE fields Rémi Denis-Courmont
2024-05-14 19:35 ` [FFmpeg-devel] [PATCH 2/2] lavc/flacdsp: optimise RVV vector type for lpc16 Rémi Denis-Courmont
2024-05-14 19:42 ` Rémi Denis-Courmont
Git Inbox Mirror of the ffmpeg-devel mailing list - see https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
This inbox may be cloned and mirrored by anyone:
git clone --mirror https://master.gitmailbox.com/ffmpegdev/0 ffmpegdev/git/0.git
# If you have public-inbox 1.1+ installed, you may
# initialize and index your mirror using the following commands:
public-inbox-init -V2 ffmpegdev ffmpegdev/ https://master.gitmailbox.com/ffmpegdev \
ffmpegdev@gitmailbox.com
public-inbox-index ffmpegdev
Example config snippet for mirrors.
AGPL code for this site: git clone https://public-inbox.org/public-inbox.git