From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.org/gmane.linux.lib.musl.general/10540 Path: news.gmane.org!.POSTED!not-for-mail From: Adhemerval Zanella Newsgroups: gmane.linux.lib.musl.general Subject: Re: Model specific optimizations? Date: Thu, 29 Sep 2016 16:14:18 -0700 Message-ID: <822cfff3-4497-9f1f-4b0c-b2b1ecd26478@linaro.org> References: <20160929142126.GB22343@voyager> <20160929152354.GK19318@brightrain.aerifal.cx> <20160929170801.GC22343@voyager> <20160929181336.GL19318@brightrain.aerifal.cx> <34de22ab-4bbe-6d23-3dfd-57779c7c99d1@linaro.org> <20160929220514.GI1280@port70.net> Reply-To: musl@lists.openwall.com NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit X-Trace: blaine.gmane.org 1475190885 13680 195.159.176.226 (29 Sep 2016 23:14:45 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Thu, 29 Sep 2016 23:14:45 +0000 (UTC) User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.3.0 To: musl@lists.openwall.com Original-X-From: musl-return-10553-gllmg-musl=m.gmane.org@lists.openwall.com Fri Sep 30 01:14:42 2016 Return-path: Envelope-to: gllmg-musl@m.gmane.org Original-Received: from mother.openwall.net ([195.42.179.200]) by blaine.gmane.org with smtp (Exim 4.84_2) (envelope-from ) id 1bpkXA-0001p1-5G for gllmg-musl@m.gmane.org; Fri, 30 Sep 2016 01:14:32 +0200 Original-Received: (qmail 30142 invoked by uid 550); 29 Sep 2016 23:14:32 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Original-Received: (qmail 30121 invoked from network); 29 Sep 2016 23:14:31 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=subject:to:references:from:message-id:date:user-agent:mime-version :in-reply-to:content-transfer-encoding; bh=cRK1riica77sds5f0dCIAXxhp5kRiDtm80U+sg092/s=; b=i1R5g6icnGP6/mgOiIxjDuwmCvlXFTKqDOIdCChLjjLFjNrFEcMLQ14IO0AgCEYmIC mnX7gtZ9yKqfr4FejhGxfYcxNLT3AVKZIEG8kpPF4OceaBcloBAk2REvcr5wDwls05af ue24ZwBGCL82v+nwihKdrqhYczOwee67ocsno= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:subject:to:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-transfer-encoding; bh=cRK1riica77sds5f0dCIAXxhp5kRiDtm80U+sg092/s=; b=EuNgnkVOpb+pVjQ/qyPBbUSg3wix3sDBCNROVmU0NveESymnjdCFj4yq6afay2c7WU jhiXG/P5iXK+F9rHAubnRKS+DTeLI2BqEKK+S/eH7BiRFU40UCelP7vI0LLH6sWvQQHF XGDwDobHe7jBM5WmL8OTmsxAcXDMO4y7SfGrIhX5+63fCCmESOmbb6b/mEnSljCL9QTd cTDwPDQXROKswv35YMrzsA8egLFrihjMvQB5tzgMFU5upsBmBjc4YQQis/wqATeV7Z3D t4od7hT9eoe9klEF+0q+v48Yv5nlg7UL1TVJp7t71/HzXisnfOj8pOpUEQCngKhVdlpd yXlA== X-Gm-Message-State: AA6/9RmJTg8V6Xy648D7btQ14T5L7DRXWqg7tlILnW1wsvvKEYCH2V/aI4aUKw8PDaFFTA0R X-Received: by 10.66.235.100 with SMTP id ul4mr6695777pac.50.1475190859672; Thu, 29 Sep 2016 16:14:19 -0700 (PDT) In-Reply-To: <20160929220514.GI1280@port70.net> Xref: news.gmane.org gmane.linux.lib.musl.general:10540 Archived-At: On 29/09/2016 15:05, Szabolcs Nagy wrote: > * Adhemerval Zanella [2016-09-29 11:52:44 -0700]: >> On 29/09/2016 11:13, Rich Felker wrote: >>> On Linux it's supposed to be the kernel which detects availability of >>> features (either by feature-specific cpu flags or translating a model >>> to flags) but I don't see anything for fsqrt on ppc. :-( How/why did >>> they botch this? >> >> Maybe because recent power work on kernel is POWER oriented, where fsqrt >> is define since POWER4. However some more recent freescale chips (such >> as e5500 and e6500) also decided to not add fsqrt instruction. >> >> With GCC you can check for _ARCH_PPCSQ to see if current arch flags >> allows fsqrt. From runtine I presume programs can check for hwcap bit >> PPC_FEATURE_POWER4, however it does not help on non-POWER chips which >> do support fsqrt. >> > > how can distros deal with this? > > do they require POWER4? > I do not really know how is the current approach for powerpc{32,64} distros, but I recall that both RHEL and SLES used to provided arch specific libc.so build/optimized for each chips (default, power4, powerX). The powerpc64le have a current minimum ISA of 2.07 (power8) with both complete fp and VSX, so it should not have this issue.