From my understanding, to use larger group multipliers, one needs to utilize vlse64 (8x8) vlse128 (16x16).
However, due to the use in tests of ptr = img2 + y * WIDTH + x; d2 = call_ref(NULL, img1, ptr, WIDTH, h); d1 = call_new(NULL, img1, ptr, WIDTH, h); will get: pix_abs_1_0_rvv_i32 (fatal signal 7: Bus error) Because it can only load according to e8, it seems there's no way to use larger group multipliers. Rémi Denis-Courmont <r...@remlab.net> 于2024年2月9日周五 03:41写道: > Le keskiviikkona 7. helmikuuta 2024, 2.01.23 EET flow gg a écrit : > > I think in most cases it is like this, but specifically for this > function, > > using Reduction only once would be slower. > > > > The currently submitted version roughly takes: > > pix_abs_0_0_rvv_i32: 136.2 > > > > The version that uses Reduction only once takes: > > pix_abs_0_0_rvv_i32: 169.2 > > You're only using one vector and half a vector respectively, so the > logarithmic time of the sum is relatively small. > > But are you sure that it wouldn't be faster to process multiple rows and > larger group multiplers? > > > Here is the implementation of the version that uses it only once: > > > > func ff_pix_abs16_temp_rvv, zve32x > > vsetivli zero, 16, e32, m4, ta, ma > > vmv.v.i v24, 0 > > vmv.s.x v0, zero > > 1: > > vsetvli zero, zero, e8, m1, tu, ma > > vle8.v v4, (a1) > > vle8.v v12, (a2) > > addi a4, a4, -1 > > vwsubu.vv v16, v4, v12 > > add a1, a1, a3 > > vwsubu.vv v20, v12, v4 > > vsetvli zero, zero, e16, m2, tu, ma > > vmax.vv v16, v16, v20 > > add a2, a2, a3 > > vwadd.wv v24, v24, v16 > > bnez a4, 1b > > > > vsetvli zero, zero, e32, m4, ta, ma > > vwredsumu.vs v0, v24, v0 > > vmv.x.s a0, v0 > > ret > > endfunc > > > > Rémi Denis-Courmont <r...@remlab.net> 于2024年2月7日周三 00:58写道: > > > > > Hi, > > > > > > To sum a vector, you should only reduce once at the end of the > function, > > > c.f. > > > how it's done in existing scalar products. Reduction instructions are > > > (intrinsically) slow. > > > > > > -- > > > 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-requ...@ffmpeg.org with subject "unsubscribe". > > > -- > 雷米‧德尼-库尔蒙 > 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-requ...@ffmpeg.org with subject "unsubscribe". > _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".