Le 9 février 2024 00:39:38 GMT+02:00, flow gg <hlefthl...@gmail.com> a écrit : >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.
vlse128.v requires 128-bit elements, which no hardware supports. vlse64.v works just fine; we're already using it. There's also the possibility of segmented strided loads, or simply multiple unit loads. In any case, unrolling one way or other should improve performance. > > > >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". _______________________________________________ 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".