From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ffbox0-bg.mplayerhq.hu (ffbox0-bg.ffmpeg.org [79.124.17.100]) by master.gitmailbox.com (Postfix) with ESMTP id 1B7234764F for ; Thu, 16 May 2024 16:49:01 +0000 (UTC) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id E1FFE68D47A; Thu, 16 May 2024 19:48:48 +0300 (EEST) Received: from ursule.remlab.net (vps-a2bccee9.vps.ovh.net [51.75.19.47]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id 47A6168D3E9 for ; Thu, 16 May 2024 19:48:41 +0300 (EEST) Received: from basile.remlab.net (localhost [IPv6:::1]) by ursule.remlab.net (Postfix) with ESMTP id CB183C013D for ; Thu, 16 May 2024 19:48:40 +0300 (EEST) From: =?UTF-8?q?R=C3=A9mi=20Denis-Courmont?= To: ffmpeg-devel@ffmpeg.org Date: Thu, 16 May 2024 19:48:38 +0300 Message-ID: <20240516164840.19025-2-remi@remlab.net> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240516164840.19025-1-remi@remlab.net> References: <20240516164840.19025-1-remi@remlab.net> MIME-Version: 1.0 Subject: [FFmpeg-devel] [PATCHv4 2/4] lavc/flacdsp: optimise RVV vector type for lpc16 X-BeenThere: ffmpeg-devel@ffmpeg.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: FFmpeg development discussions and patches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: FFmpeg development discussions and patches Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" Archived-At: List-Archive: List-Post: 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 1 48.0 214.7 95.2 2 64.7 214.2 94.7 3 79.7 213.5 94.5 4 96.2 196.5 94.2 # 5 111.0 195.7 118.5 6 127.0 211.2 102.0 7 143.7 194.2 101.5 8 175.7 193.2 101.2 # 9 176.2 224.2 126.0 10 191.5 192.0 125.5 11 224.5 191.2 124.7 12 223.0 190.2 124.2 13 239.2 189.5 123.7 14 253.7 188.7 139.5 15 286.2 188.0 122.7 16 284.0 187.0 122.5 # 17 300.2 186.5 186.5 18 314.0 185.5 185.7 19 329.7 184.7 185.0 20 343.0 184.2 184.2 21 358.7 199.2 183.7 22 371.7 182.7 182.7 23 387.5 181.7 182.0 24 400.7 181.0 181.2 25 431.5 180.2 196.5 26 443.7 195.5 196.0 27 459.0 178.7 196.2 28 470.7 177.7 194.2 29 470.0 177.0 193.5 30 481.2 176.2 176.5 31 496.2 175.5 175.7 32 507.2 174.7 191.0 # # Power of two boundary. 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. flac lpc16 --- libavcodec/riscv/flacdsp_init.c | 2 +- libavcodec/riscv/flacdsp_rvv.S | 5 +++-- 2 files changed, 4 insertions(+), 3 deletions(-) diff --git a/libavcodec/riscv/flacdsp_init.c b/libavcodec/riscv/flacdsp_init.c index 4f1652dbe7..735aec0691 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; # if (__riscv_xlen >= 64) diff --git a/libavcodec/riscv/flacdsp_rvv.S b/libavcodec/riscv/flacdsp_rvv.S index 6287faa260..e1a20ce8e1 100644 --- a/libavcodec/riscv/flacdsp_rvv.S +++ b/libavcodec/riscv/flacdsp_rvv.S @@ -20,8 +20,9 @@ #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 + vtype_vli t0, a2, t2, e32, ta, ma + 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".