Date: Thu, 25 Nov 2021 18:16:54 +0100 (CET) From: freebsd@oldach.net (Helge Oldach) To: allanjude@freebsd.org (Allan Jude) Cc: manu@bidouilliste.com, src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org Subject: Re: git: 32a2fed6e71f - stable/13 - openssl: Fix detection of ARMv7 and ARM64 CPU features Message-ID: <202111251716.1APHGsC7018508@nuc.oldach.net> In-Reply-To: <9bf8a967-de50-9072-40cb-08d2798594dc@freebsd.org> from Allan Jude at "25 Nov 2021 11:54:06"
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Allan Jude wrote on Thu, 25 Nov 2021 17:54:06 +0100 (CET): > On 11/25/2021 10:31 AM, Helge Oldach wrote: > > Allan Jude wrote on Thu, 25 Nov 2021 16:09:25 +0100 (CET): > >> On 11/25/2021 2:38 AM, Helge Oldach wrote: > >>> hmo@p48 ~ $ for f in 0 1 2 3 8 16 32 64 128 ; do echo -n $f:; env OPENSSL_armcap=$f openssl speed -evp aes-256-gcm 2>&1 | tail -1 | cut -wf7; done > >>> 0:42295.15k > >>> 1:23891.19k > >>> 2:42208.57k > >>> 3:23970.56k > >>> 8:42354.98k > >>> 16:42199.06k > >>> 32:size > >>> Illegal instruction (core dumped) > >>> 64:42322.42k > >>> 128:42275.00k > >>> hmo@p48 ~ $ > >>> > >>> So I guess HWCAP_FP is the culprit? Maybe related to hard/soft floating > >>> point math which indeed is kind of special on the Pi? > >> > >> So yeah, the issue seems to be that floating point on the RPi4 is slower > >> than not, but now openssl (properly) detects that the CPU advertises > >> support for it. > >> > >> As seen elsewhere in the thread, most other ARM platforms get a very > >> significant speed boost. > > > > So can we disable FP within OpenSSL for the RPi by default? This commit > > basically introduced a regression for this platform and I think that > > should be fixed. > > > > Or it the root cause a suboptimal FP implementation that is not adequate > > for the RPi? > > > > Kind regards > > Helge > > > > The root cause is that the RPi4 advertises support for FP, but its FP is > slow. > > I don't know that there is an easy way to detect the RPi4 specifically. > You might be able to just disable the FP bit by setting > OPENSSL_armcap=~1 globally, or maybe via openssl.conf? Sure can do that locally - but again: This commit is basically a regression which IMHO should be fixed in a way not requiring users to tweak things? Kind regards Helge
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