Date: Thu, 16 Oct 2008 00:45:48 +0400 From: Stanislav Sedov <stas@FreeBSD.org> To: Alexander Motin <mav@FreeBSD.org> Cc: zbeeble@gmail.com, freebsd-arm@freebsd.org, freebsd-current@freebsd.org, "M. Warner Losh" <imp@bsdimp.com>, freebsd-mobile@freebsd.org Subject: Re: RFC: PCI SD host controller driver & mmc/mmcsd modules improvements Message-ID: <20081016004548.437cba9d.stas@FreeBSD.org> In-Reply-To: <48F651A7.3040001@FreeBSD.org> References: <5f67a8c40810052226k3070a11ah463a819c677f6307@mail.gmail.com> <20081008113848.c9b44354.webmaster@kibab.com> <20081012171201.da4da754.webmaster@kibab.com> <20081013.110310.-1622595361.imp@bsdimp.com> <48F651A7.3040001@FreeBSD.org>
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--Signature=_Thu__16_Oct_2008_00_45_48_+0400_gpvxnSXKe9UYcK1e Content-Type: text/plain; charset=US-ASCII Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, 15 Oct 2008 23:25:11 +0300 Alexander Motin <mav@FreeBSD.org> mentioned: >=20 > Completely fortunate I have noticed that number of iterations depends on= =20 > my laptop power source. After small investigation I have found that it=20 > actually depends on dev.cpu.0.freq value. With default value 2400 I have= =20 > only several iterations. But every double frequency decrease doubles=20 > iteration count. With minimum value 100MHz I have more then 100=20 > iterations. Same time it doesn't looks like this time is a real wall=20 > time. It looks like DELAY() used in a loop has some problems with time=20 > counting. >=20 What do you mean? DELAY(9) on your laptop doesn't correspond to the real time? AFAIK, DELAY(9) relies on current timecounter for time accountiong, so there might be problems with it. Have you tried switching the kern.timecounter.hardware sysctl to see if it will affect results? --=20 Stanislav Sedov ST4096-RIPE --Signature=_Thu__16_Oct_2008_00_45_48_+0400_gpvxnSXKe9UYcK1e Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.9 (FreeBSD) iEYEARECAAYFAkj2VoEACgkQK/VZk+smlYHA5wCeIgg4IPiIQihQ3sVJ5IzawUaK nGgAnid2uyjyJbK0jty1Tp3zl+gXNRn7 =WF8Y -----END PGP SIGNATURE----- --Signature=_Thu__16_Oct_2008_00_45_48_+0400_gpvxnSXKe9UYcK1e--
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