Date: Fri, 25 May 2012 16:05:56 -0400 From: Jung-uk Kim <jkim@FreeBSD.org> To: Andriy Gapon <avg@freebsd.org> Cc: freebsd-stable@freebsd.org, Yamagi Burmeister <lists@yamagi.org>, seanbru@yahoo-inc.com Subject: Re: [stable 9] broken hwpstate calls Message-ID: <4FBFE624.1020208@FreeBSD.org> In-Reply-To: <4FBFDFFB.9020501@FreeBSD.org> References: <1337319129.2915.4.camel@powernoodle-l7> <4FB6765A.2050307@FreeBSD.org> <1337710214.2916.8.camel@powernoodle-l7.corp.yahoo.com> <20120525163653.b61a08e2.lists@yamagi.org> <4FBFA9A9.7020806@FreeBSD.org> <4FBFBD39.7000105@FreeBSD.org> <4FBFDFFB.9020501@FreeBSD.org>
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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 2012-05-25 15:39:39 -0400, Andriy Gapon wrote: > on 25/05/2012 20:11 Jung-uk Kim said the following: >> I just looked through the BKDG and I think you should definitely >> check MSRC001_0071[18:16]. MSRC001_0063[2:0] is "SharedC" but >> MSRC001_0062[2:0] and MSRC001_0071[18:15] are "Not-same-for-all". >> I think this means writing a P-state to MSRC001_0062[2:0] will be >> reflected in MSRC001_0070[18:16] first, then MSRC001_0071[18:16] >> gets updated when the P-state transition is complete. >> MSRC001_0063[2:0] will only change when all cores in a compute >> unit is in sync., which may be too late. >> > [snip] >> I think we should check. > > Jung-uk, > > if we decide so, then I think that we could still keep the things > "simple". As we currently use the "wholesale" approach (all CPUs > are set to the same P-state regardless of topology), then we could > first make a pass of writing the MSR on all processors with a new > P-state value and then make another pass of checking via MSR > C001_0063 that the P-state is acquired. No, I believe checking MSRC001_0071[18:16] is much simpler if it works. And it does not break current cpufreq(4) design principles. Jung-uk Kim -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (FreeBSD) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAk+/5iQACgkQmlay1b9qnVOHLgCfY0ELt5oN1hml8S+bDGSHbOux bj4AoKisSh9DlK46U+LFthaSGicp/+Hc =BYej -----END PGP SIGNATURE-----
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