Date: Wed, 23 Jun 2004 12:58:19 -0700 (PDT) From: Nate Lawson <nate@root.org> To: YONETANI Tomokazu <qhwt+freebsd-acpi@les.ath.cx> Cc: freebsd-acpi@freebsd.org Subject: Re: cx_usage Message-ID: <20040623125803.N86954@root.org> In-Reply-To: <20040619101905.GA55457@les.ath.cx> References: <20040616131055.GA37637@les.ath.cx> <20040618052615.GA48947@les.ath.cx> <20040618192739.W52398@root.org> <20040619101905.GA55457@les.ath.cx>
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On Sat, 19 Jun 2004, YONETANI Tomokazu wrote: > On Fri, Jun 18, 2004 at 07:27:57PM -0700, Nate Lawson wrote: > > On Fri, 18 Jun 2004, YONETANI Tomokazu wrote: > > > On Wed, Jun 16, 2004 at 10:10:55PM +0900, YONETANI Tomokazu wrote: > > > > What do you think about the following changes? > > > > > > > > - print 100% instead of 99% when there's only 1 Cx state, and 0% > > > > when the sum is zero. > > > > - two digits from fractional part of each percentage are shown; > > > > my Laptop PC barely enters into C3 state and hw.acpi.cpu.cx_usage > > > > is almost always "0% 99% 0%" after revision 1.39. it's now shown as > > > > "0.00% 99.96% 0.03%" > > > > > > Actually, cpu_cx_stats[i] * 100 may not fit in u_int and would print > > > incorrect value as values grow. Please try this instead. > > > > Thank you. I committed this with minor changes. > > Thanks. But I found myself stupid: > > whole = cpu_cx_stats[i] * 100; > > cpu_cx_stats[i] needs a cast into u_int64_t, otherwise multiplication > is still performed as 32bit-integer and will overflow before assigned > to `whole', and using u_int64_t variables is worthless. I tend to assume > that there's an automatic upgrade of precision to that of the left-hand > side operand, but it's pretty wrong. I should have noticed this while > testing the patch if I kept the laptop turned on a bit longer. > I'm sorry. > You're correct. I'll commit the fix in a little while. -Nate
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