From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-3.1 required=5.0 tests=DKIM_ADSP_CUSTOM_MED, DKIM_INVALID,DKIM_SIGNED,FREEMAIL_FROM,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED,RCVD_IN_MSPIKE_H3,RCVD_IN_MSPIKE_WL autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 3399 invoked from network); 28 Aug 2021 20:28:23 -0000 Received: from mother.openwall.net (195.42.179.200) by inbox.vuxu.org with ESMTPUTF8; 28 Aug 2021 20:28:23 -0000 Received: (qmail 3999 invoked by uid 550); 28 Aug 2021 20:28:21 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Reply-To: musl@lists.openwall.com Received: (qmail 3981 invoked from network); 28 Aug 2021 20:28:21 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:reply-to:from:date:message-id :subject:to; bh=KlD513s4AmZrc87gBFJTdAUiLbcqwPnAYrchRvYkBf0=; b=V0S3+F7Ci2nkTYK7JODny1YlWpdOrRP34Xi7WtMt9+CJPV4q4XKIF5tzJRKMHbTk8C vrBN8fVglnG78zf5XScewtklEik+XK6Lyosto0vXawhtYQrbrQcNCRUE4YGYwEAB6rbv 1VDalM+V4HjvZgz1O3l8ilWsQz31TfFKwXTOkIzeuVU+dCeg99P72zQfHRL3n2gCHwY+ feFv18ZVo/EpndvqVNvNumoJql/i3ITpVM5jwWcYXoUo3a+zf1uDT2cgu57LzgOHiyAc lsV0WtxUBl8hcpnxEWyn/Lbi6vhmuJe+l+u/5nGUZ71YGW8aSziRgXlZXgc/yvmHNL18 GYRA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:reply-to :from:date:message-id:subject:to; bh=KlD513s4AmZrc87gBFJTdAUiLbcqwPnAYrchRvYkBf0=; b=VjPYncRNHhFgV83N/Q5AKxcGA1wU6AKhLo03vTXZkYqghV9vnjEXDKkNXJXHSyA3Q6 kjpH7ceo3Egw8JcibCKiiso4gpK5FoE3FM1A6L2ZfmC/c3wgvRGGfazxTTW2pgboCkEb sfpgOf3sLBW0Z0X02LzJM4qoac1pmDw0X+x4nCsBCfP9FZJYFgthlifGhx1MNH79nDGy OnFJPjYthXN0DVzTGAw8hiU4xYASBSooDv1+QX/eCTz5pcAtX1par4HajeeRrvPQX6gZ Ib7Iyel7FtBdi7+rJazfpspAm4feQ3QWWT4rHgJqG4Hwe/O8TptL7afm2u7G8uwz6het xQTg== X-Gm-Message-State: AOAM533QN52utOErg+xmy1Y/1XPa8fpNdO0kNoeFZbqCK3AXCttDuWgh I1wDOECQDdY6jdyuygph3f89pNkg5lJbG4SZCIvCrDfInxqvDA== X-Google-Smtp-Source: ABdhPJyeeLzUl06FNcU4f4gJ3YIMK4kMQFGXgJUCxp90wvpVUEcO4+r7/LdUi2GDue3wgOY+B319Xo6q3oImgOPvJHw= X-Received: by 2002:a63:5252:: with SMTP id s18mr14110832pgl.94.1630182487554; Sat, 28 Aug 2021 13:28:07 -0700 (PDT) MIME-Version: 1.0 References: <4e37b6c4.19be.17b8bc750df.Coremail.13824125580@163.com> <20210828195330.GZ13220@brightrain.aerifal.cx> In-Reply-To: <20210828195330.GZ13220@brightrain.aerifal.cx> From: Jeffrey Walton Date: Sat, 28 Aug 2021 16:27:49 -0400 Message-ID: To: musl@lists.openwall.com Content-Type: text/plain; charset="UTF-8" Subject: Re: [musl] Why the musl libc did not support neon simd acceleartor officially on mem* operations? On Sat, Aug 28, 2021 at 3:53 PM Rich Felker wrote: > > On Sat, Aug 28, 2021 at 04:01:40PM +0800, tugouxp wrote: > > HI guys: > > I found that the current implmention of musl arm port memcpy.S and > > other mem*.S operations did not use arm neon instructions, this > > seems differenct with other counterparts like newlibc, glibc and > > bonic libc, which all impl. the neon version of mem* operations. so > > could you tell me why? is there and concern about on this in musl? > > if i want to imple my self imple. how to do this, is there any > > matual pathches to use? > > Generally we don't have any significant asm implementations that > depend on non-baseline extensions to the ISA. The same is true for x86 > where no sse/avx is used. Out of curiosity, does anyone use Hardware Capabilities (https://linux.die.net/man/8/ld-linux) nowadays? Something like a /usr/lib/musl, /usr/lib/sse/musl, /usr/lib/avx/musl, /usr/lib/neon/musl, etc? The benefit to using it is no runtime switching. The switching occurs at load time, not runtime. I know of a handful of libraries that could benefit from the speed up on a critical path with an arch specific implementation. But I think most libraries don't need it. Jeff