From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D5DA73F9FC for ; Mon, 29 Jan 2024 18:16:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706552177; cv=none; b=Rklgu5FGnZJQ3yIYCXABOLP57utNp2gk8ZldY6NRiJLJ/FrIgeB8MVxdqiaM5kUR6SVxLK5n+ImX6Xklp7t6z70tLoSRxSSrVHYy+YZJhJ/QacE7XLoOJfOeH4dxNW1wl2SzxYkVHxJX7SzxvpBQ7Q3YqhuEdWJE9vGi9QMBL5w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706552177; c=relaxed/simple; bh=4eYLj/Lm5IOPUr7af+2C6a/UQ1OO1uxY23YBH7rnuMQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=tHGv59MlwtfbuaeAHDEvEtlZauyhVvcCMBH7I80Mqpqo7seG0/+DZyzV7hOrUHM9OVhM79k7tXP6WvdETJFSzy57gXDpfrr1MLEDiiFtCrurahnM6jDQFL33x+lfWTgY067pFEQuBWcwP1Glyfw+ugiBsbTG5gWXCJokc8SpubQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=P6KeVEXS; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="P6KeVEXS" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1DE0AC43390; Mon, 29 Jan 2024 18:16:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1706552177; bh=4eYLj/Lm5IOPUr7af+2C6a/UQ1OO1uxY23YBH7rnuMQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=P6KeVEXSToGyeem1pchNMajeFGtoD9G9sIiQiQEfXKACNlusnFQ+nElZ28J5l1dTf 2lHc6BUcIcO94lv0eiRCXRNh0PlwylRLi2AunxuduIesrx0mL3dkIJk6lK8Ve6bEu3 5MBuCN43X5Ny0/9blfPv5VhHJ+Tfi2JuTdxn/UpCS5yrXTcy70VDCmLzt0ONykvGWB kGKs+4RzzGHSW+Vl8Y66WkEPa99kpss/UvoaBlITv7TiXCtcippQI836W5nadNMS4u tDu+oKcjn7DlPvMBaJNzYGrlLGtpCvdWDh1Ena/LF8pHJAQHApmlpohzNX0zey340P VBAHcZ7w/z/mA== Date: Mon, 29 Jan 2024 18:16:13 +0000 From: Conor Dooley To: Jisheng Zhang Cc: Paul Walmsley , Palmer Dabbelt , Albert Ou , linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 0/3] riscv: optimize memcpy/memmove/memset Message-ID: <20240129-prelaw-tweet-ae59a90ded20@spud> References: <20240128111013.2450-1-jszhang@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="d1n2JiHAv+OvTEWE" Content-Disposition: inline In-Reply-To: <20240128111013.2450-1-jszhang@kernel.org> --d1n2JiHAv+OvTEWE Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sun, Jan 28, 2024 at 07:10:10PM +0800, Jisheng Zhang wrote: > This series is to renew Matteo's "riscv: optimized mem* functions" > sereies. >=20 > Compared with Matteo's original series, Jisheng made below changes: > 1. adopt Emil's change to fix boot failure when build with clang > 2. add corresponding changes to purgatory > 3. always build optimized string.c rather than only build when optimize > for performance > 4. implement unroll support when src & dst are both aligned to keep > the same performance as assembly version. After disassembling, I found > that the unroll version looks something like below, so it acchieves > the "unroll" effect as asm version but in C programming language: > ld t2,0(a5) > ld t0,8(a5) > ld t6,16(a5) > ld t5,24(a5) > ld t4,32(a5) > ld t3,40(a5) > ld t1,48(a5) > ld a1,56(a5) > sd t2,0(a6) > sd t0,8(a6) > sd t6,16(a6) > sd t5,24(a6) > sd t4,32(a6) > sd t3,40(a6) > sd t1,48(a6) > sd a1,56(a6) > And per my testing, unrolling more doesn't help performance, so > the "c" version only unrolls by using 8 GP regs rather than 16 > ones as asm version. > 5. Add proper __pi_memcpy and __pi___memcpy alias > 6. more performance numbers. >=20 > Per my benchmark with [1] on TH1520, CV1800B and JH7110 platforms, > the unaligned medium memcpy performance is running about 3.5x ~ 8.6x > speed of the unpatched versions's! Check patch1 for more details and > performance numbers. >=20 > Link:https://github.com/ARM-software/optimized-routines/blob/master/strin= g/bench/memcpy.c [1] >=20 > Here is the original cover letter msg from Matteo: > Replace the assembly mem{cpy,move,set} with C equivalent. >=20 > Try to access RAM with the largest bit width possible, but without > doing unaligned accesses. >=20 > A further improvement could be to use multiple read and writes as the > assembly version was trying to do. >=20 > Tested on a BeagleV Starlight with a SiFive U74 core, where the > improvement is noticeable. However, with allmodconfig it doesn't compile: Redirect to /build/tmp.zzMIlhgQQo and /build/tmp.vxnoxu8G5e Tree base: 0c526539d432 ("riscv: optimized memcpy") Building the whole tree with the patch ../arch/riscv/lib/string.c:118:7: error: expected identifier or '(' ../arch/riscv/lib/string.c:118:7: error: expected ')' ../arch/riscv/lib/string.c:143:7: error: expected identifier or '(' ../arch/riscv/lib/string.c:143:7: error: expected ')' ../arch/riscv/lib/string.c:118:7: error: expected identifier or '(' ../arch/riscv/lib/string.c:118:7: error: expected ')' ../arch/riscv/lib/string.c:143:7: error: expected identifier or '(' ../arch/riscv/lib/string.c:143:7: error: expected ')' Seems to be the case both with llvm and gcc. Cheers, Conor. --d1n2JiHAv+OvTEWE Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQRh246EGq/8RLhDjO14tDGHoIJi0gUCZbfrbQAKCRB4tDGHoIJi 0tfSAP9CXefieMdiPqbq7pdjY+14U99AxgMlsgdjf8Ba7tagMQD/bq4CepFhnrUJ AmdXmVbmVEhI6YWXz3uuEssFY1Sg5A4= =DP0s -----END PGP SIGNATURE----- --d1n2JiHAv+OvTEWE--