Date: Mon, 8 Feb 2021 21:16:52 +0100 From: Mike Knell <m@blat.at> To: Elwood Downey <elwood.downey@gmail.com> Cc: freebsd-arm@freebsd.org Subject: Re: freebsd 6x slower than Raspbian 10 buster on RPi 4b Message-ID: <30261E8B-BFCE-4C3B-91A0-48A41BEB0455@blat.at> In-Reply-To: <CAL98DL44SPbiT9EHuxrDSzttUyv0coj6nGNJ2VpYArsfujP_bg@mail.gmail.com> References: <CAL98DL44SPbiT9EHuxrDSzttUyv0coj6nGNJ2VpYArsfujP_bg@mail.gmail.com>
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> On 8 Feb 2021, at 21:12, Elwood Downey <elwood.downey@gmail.com> = wrote: >=20 > Hello all! >=20 > Just wanted to share a comparison I did between freebsd and raspbian = on the > same RPi 4b with 1 GB RAM. I wrote a tiny C++ program that creates > pthreads, each of which mallocs an array and spins filling it with = sqrtf of > the array index. Setting it to 3 threads (the hw has 4 cores), I found > freebsd takes consistently 6.5x wall-clock time longer than with = raspbian. > Below are the sessions for each showing pertinent details. Attached is = the > program itself (if it doesn't make it through the newsgroup, mail me = direct > for a copy). One good news is the thread overhead for freebsd is about = 100x > smaller so kudos to the scheduler. >=20 > This is surprising and disappointing. Any comments welcome, especially = what > I'm doing wrong here. Thank you for your time. It looks to me like you=E2=80=99re running a CURRENT snapshot - this is = built with the debugging kernel config which has a major performance impact. If you build a kernel using the CURRENT-NODEBUG config (i.e. cd /usr/src &&=20= make buildkernel KERNCONF=3DCURRENT-NODEBUG ) you=E2=80=99ll probably = find that speeds things up a bit. -CURRENT is development code and should be treated as = such. Mike=
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