From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.org/gmane.linux.lib.musl.general/3623 Path: news.gmane.org!not-for-mail From: Andre Renaud Newsgroups: gmane.linux.lib.musl.general Subject: Re: Thinking about release Date: Thu, 11 Jul 2013 16:04:21 +1200 Message-ID: References: <20130613012517.GA5859@brightrain.aerifal.cx> <20130613014314.GC29800@brightrain.aerifal.cx> <20130709053711.GO29800@brightrain.aerifal.cx> <20130711033754.GL29800@brightrain.aerifal.cx> Reply-To: musl@lists.openwall.com NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-Trace: ger.gmane.org 1373515474 15024 80.91.229.3 (11 Jul 2013 04:04:34 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Thu, 11 Jul 2013 04:04:34 +0000 (UTC) Cc: musl@lists.openwall.com To: Rich Felker Original-X-From: musl-return-3627-gllmg-musl=m.gmane.org@lists.openwall.com Thu Jul 11 06:04:35 2013 Return-path: Envelope-to: gllmg-musl@plane.gmane.org Original-Received: from mother.openwall.net ([195.42.179.200]) by plane.gmane.org with smtp (Exim 4.69) (envelope-from ) id 1Ux87P-0002H5-DS for gllmg-musl@plane.gmane.org; Thu, 11 Jul 2013 06:04:35 +0200 Original-Received: (qmail 26502 invoked by uid 550); 11 Jul 2013 04:04:33 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: Original-Received: (qmail 26491 invoked from network); 11 Jul 2013 04:04:33 -0000 X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:x-gm-message-state; bh=x4ISPjg2Q1LGU+1yl48xfOWvQCnIdYUl5rhemCKmIxA=; b=UebtB0xuL1q0Xl8Ds28FY86SyA7fxYgtNunZP7baHlzBKQ13/FVjqGh/UpvV3zhBAb febEXsJaT46ZfugFGwz+XRP67Lans0VtpqsDEw9IwLWMhdlAP6KMCfKQ70w2XX2vf7vG CdnRIKMpo1ZZAUHwXf7J0Lb0IIidrQ+/m+Ne8TmkzzzsuD9f64Y2mXEaX0fMFL9YpNec 92WVcSbfN/pFHJbMUETjgI9rsNwrXQbGJjW1OwU+1hZeshd70lUAe/MDANYkJdrqxRGN AHlNLZsEN+H1FRJVVpbwRSkDhSu8TAM4Tzs1AKP8eMjHJNNo1d0CUU2XZXdQk0oQ6rJH Z8jw== X-Received: by 10.52.165.239 with SMTP id zb15mr17365816vdb.44.1373515461818; Wed, 10 Jul 2013 21:04:21 -0700 (PDT) In-Reply-To: <20130711033754.GL29800@brightrain.aerifal.cx> X-Gm-Message-State: ALoCoQl3thVMK6vv8/VK7W+4myC0y0/UpK3ihqhTTrtX8EcfCl+HAR8Wd7baYmwBUz4mJulIlLOP Xref: news.gmane.org gmane.linux.lib.musl.general:3623 Archived-At: Hi Rich, >> Rich - do you have any comments on whether either the C or assembler >> variants of memcpy might be suitable for inclusion in musl? > > I would say either might be, but it looks like if we want competitive > performance, some asm will be needed (either inline or full). My > leaning would be to go for something simpler than the asm you've been > experimenting with, but with same or better performance, if this is > possible. I realize the code is not that big as-is, in terms of binary > size, but it's big from an "understanding it" perspective and I don't > like big asm blobs that are hard for somebody to look at and say "oh > yeah, this is clearly right". > > Anyway, the big questions I'd still like to get answered before moving > forward is whether the cache line alignment has any benefit. I certainly appreciate the need for concise, well understood, easily readable code. I can't see any obvious reason why this shouldn't work, although the assembler as it stands makes pretty heavy use of all the registers, and I can't immediately see how to rework it to free up 2 more (I can free up 1 by dropping the attempted preload). Given my (lack of) skills with ARM assembler, I'm not sure I'll be able to look too deeply into either of these options, but I'll have a go at the inline ASM version to force 8*4byte loads to see if it improves things. Regards, Andre