Date: Mon, 3 Dec 2007 10:21:13 -0800 From: "Kip Macy" <kip.macy@gmail.com> To: "Joseph Koshy" <jkoshy@freebsd.org> Cc: cvs-src@freebsd.org, src-committers@freebsd.org, cvs-all@freebsd.org Subject: Re: cvs commit: src/sys/dev/hwpmc hwpmc_x86.c Message-ID: <b1fa29170712031021j3cad6f4bq179d6312f6c791a6@mail.gmail.com> In-Reply-To: <200712031050.lB3AowcL055057@repoman.freebsd.org> References: <200712031050.lB3AowcL055057@repoman.freebsd.org>
next in thread | previous in thread | raw e-mail | index | archive | help
On Dec 3, 2007 2:50 AM, Joseph Koshy <jkoshy@freebsd.org> wrote: > jkoshy 2007-12-03 10:50:58 UTC > > FreeBSD src repository > > Modified files: (Branch: RELENG_7) > sys/dev/hwpmc hwpmc_x86.c > Log: > MFC r1.6: > "Revert revision 1.4. > > Intel CPUs with family 0x6, model 0xE and later (i.e., Intel Core(TM)) > have a PMC architecture that differs somewhat from previous CPUs in > family 0x6. Even though the basic programming model is similar, the > documented set of legal values that may be loaded into their PMC MSRs > differs from that of the previous PMCs in family 0x6 and reusing bit > values legal for the older PMCs could result in undefined behaviour in > the general case." Can you say a little more about what the differences are or where one could find a discussion of them without wading through different processor model revisions? Kris, SCC, and I have been obtaining sensible results using 0xE and 0xF for the small set of sampling operations that we use. -Kip
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?b1fa29170712031021j3cad6f4bq179d6312f6c791a6>