From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dominik Brodowski Subject: Re: [PATCH 7/8] latency must be in _nano_seconds Date: Thu, 20 Nov 2003 19:31:33 +0100 Sender: cpufreq-bounces+glkc-cpufreq=gmane.org@www.linux.org.uk Message-ID: <20031120183133.GA4425@brodo.de> References: <20031119183330.GH20576@brodo.de> <20031119190725.GA5653@redhat.com> Mime-Version: 1.0 Return-path: Content-Disposition: inline In-Reply-To: <20031119190725.GA5653@redhat.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: cpufreq-bounces+glkc-cpufreq=gmane.org@www.linux.org.uk Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Dave Jones Cc: cpufreq@www.linux.org.uk On Wed, Nov 19, 2003 at 07:07:25PM +0000, Dave Jones wrote: > On Wed, Nov 19, 2003 at 07:33:30PM +0100, Dominik Brodowski wrote: > > > return cpufreq_frequency_table_cpuinfo(policy, &p4clockmod_table[0]); > > diff -ruN linux-original/arch/i386/kernel/cpu/cpufreq/powernow-k7.c linux/arch/i386/kernel/cpu/cpufreq/powernow-k7.c > > --- linux-original/arch/i386/kernel/cpu/cpufreq/powernow-k7.c 2003-11-19 17:06:10.571868800 +0100 > > +++ linux/arch/i386/kernel/cpu/cpufreq/powernow-k7.c 2003-11-19 18:48:10.150551432 +0100 > > @@ -386,7 +386,7 @@ > > minimum_speed, maximum_speed); > > > > policy->governor = CPUFREQ_DEFAULT_GOVERNOR; > > - policy->cpuinfo.transition_latency = latency; > > + policy->cpuinfo.transition_latency = latency * 20; > > policy->cur = maximum_speed; > > Can we at least get a comment explaining where '20' comes from > when we add magic numbers like this? I know, and you know, but > it's a little non-obvious, and in six months time, I'll probably > have forgotten too 8) Comment added. > > diff -ruN linux-original/arch/i386/kernel/cpu/cpufreq/powernow-k8.c linux/arch/i386/kernel/cpu/cpufreq/powernow-k8.c > > --- linux-original/arch/i386/kernel/cpu/cpufreq/powernow-k8.c 2003-11-19 17:07:58.537455536 +0100 > > +++ linux/arch/i386/kernel/cpu/cpufreq/powernow-k8.c 2003-11-19 18:46:57.031667192 +0100 > > @@ -959,8 +959,8 @@ > > pol->governor = CPUFREQ_DEFAULT_GOVERNOR; > > > > /* Take a crude guess here. */ > > - pol->cpuinfo.transition_latency = ((rvo + 8) * vstable * VST_UNITS_20US) > > - + (3 * (1 << irt) * 10); > > + pol->cpuinfo.transition_latency = (((rvo + 8) * vstable * VST_UNITS_20US) > > + + (3 * (1 << irt) * 10)) * 1000; > > Ditto. This one moreso, as its quite complex to begin with. What Paul Devriendt did here I do not know, but I added a comment for the factor "1000"... Dominik Even though the core stated that cpuinfo.transition_latency needs to be in 10^(-9) s, hardly any driver set it to nanoseconds but to microseconds. So, fix up the drivers. arch/arm/mach-integrator/cpu.c | 2 +- arch/i386/kernel/cpu/cpufreq/acpi.c | 4 ++-- arch/i386/kernel/cpu/cpufreq/p4-clockmod.c | 2 +- arch/i386/kernel/cpu/cpufreq/powernow-k7.c | 6 +++++- arch/i386/kernel/cpu/cpufreq/powernow-k8.c | 7 ++++--- include/linux/cpufreq.h | 2 +- 6 files changed, 14 insertions(+), 9 deletions(-) diff -ruN linux-original/arch/arm/mach-integrator/cpu.c linux/arch/arm/mach-integrator/cpu.c --- linux-original/arch/arm/mach-integrator/cpu.c 2003-11-20 19:17:28.489660360 +0100 +++ linux/arch/arm/mach-integrator/cpu.c 2003-11-20 19:17:34.311775264 +0100 @@ -172,7 +172,7 @@ policy->governor = CPUFREQ_DEFAULT_GOVERNOR; policy->cpuinfo.max_freq = 160000; policy->cpuinfo.min_freq = 12000; - policy->cpuinfo.transition_latency = 1000; /* 1 ms, assumed */ + policy->cpuinfo.transition_latency = 1000000; /* 1 ms, assumed */ policy->cur = policy->min = policy->max = icst525_khz(&cclk_params, vco); /* current freq */ diff -ruN linux-original/arch/i386/kernel/cpu/cpufreq/acpi.c linux/arch/i386/kernel/cpu/cpufreq/acpi.c --- linux-original/arch/i386/kernel/cpu/cpufreq/acpi.c 2003-11-20 19:17:28.510657168 +0100 +++ linux/arch/i386/kernel/cpu/cpufreq/acpi.c 2003-11-20 19:17:34.312775112 +0100 @@ -578,8 +578,8 @@ /* detect transition latency */ policy->cpuinfo.transition_latency = 0; for (i=0;istate_count;i++) { - if (perf->states[i].transition_latency > policy->cpuinfo.transition_latency) - policy->cpuinfo.transition_latency = perf->states[i].transition_latency; + if ((perf->states[i].transition_latency * 1000) > policy->cpuinfo.transition_latency) + policy->cpuinfo.transition_latency = perf->states[i].transition_latency * 1000; } policy->governor = CPUFREQ_DEFAULT_GOVERNOR; policy->cur = perf->states[pr->limit.state.px].core_frequency * 1000; diff -ruN linux-original/arch/i386/kernel/cpu/cpufreq/p4-clockmod.c linux/arch/i386/kernel/cpu/cpufreq/p4-clockmod.c --- linux-original/arch/i386/kernel/cpu/cpufreq/p4-clockmod.c 2003-11-20 19:17:28.540652608 +0100 +++ linux/arch/i386/kernel/cpu/cpufreq/p4-clockmod.c 2003-11-20 19:17:34.312775112 +0100 @@ -255,7 +255,7 @@ /* cpuinfo and default policy values */ policy->governor = CPUFREQ_DEFAULT_GOVERNOR; - policy->cpuinfo.transition_latency = 1000; + policy->cpuinfo.transition_latency = 1000000; /* assumed */ policy->cur = stock_freq; return cpufreq_frequency_table_cpuinfo(policy, &p4clockmod_table[0]); diff -ruN linux-original/arch/i386/kernel/cpu/cpufreq/powernow-k7.c linux/arch/i386/kernel/cpu/cpufreq/powernow-k7.c --- linux-original/arch/i386/kernel/cpu/cpufreq/powernow-k7.c 2003-11-20 19:17:28.541652456 +0100 +++ linux/arch/i386/kernel/cpu/cpufreq/powernow-k7.c 2003-11-20 19:20:35.230271472 +0100 @@ -386,7 +386,11 @@ minimum_speed, maximum_speed); policy->governor = CPUFREQ_DEFAULT_GOVERNOR; - policy->cpuinfo.transition_latency = latency; + + /* latency is in 10 ns (look for SGTC above) for each VID + * and FID transition, so multiply that value with 20 */ + policy->cpuinfo.transition_latency = latency * 20; + policy->cur = maximum_speed; return cpufreq_frequency_table_cpuinfo(policy, powernow_table); diff -ruN linux-original/arch/i386/kernel/cpu/cpufreq/powernow-k8.c linux/arch/i386/kernel/cpu/cpufreq/powernow-k8.c --- linux-original/arch/i386/kernel/cpu/cpufreq/powernow-k8.c 2003-11-20 19:17:28.591644856 +0100 +++ linux/arch/i386/kernel/cpu/cpufreq/powernow-k8.c 2003-11-20 19:18:45.550945264 +0100 @@ -958,9 +958,10 @@ pol->governor = CPUFREQ_DEFAULT_GOVERNOR; - /* Take a crude guess here. */ - pol->cpuinfo.transition_latency = ((rvo + 8) * vstable * VST_UNITS_20US) - + (3 * (1 << irt) * 10); + /* Take a crude guess here. + * That guess was in microseconds, so multply with 1000 */ + pol->cpuinfo.transition_latency = (((rvo + 8) * vstable * VST_UNITS_20US) + + (3 * (1 << irt) * 10)) * 1000; if (query_current_values_with_pending_wait()) return -EIO; diff -ruN linux-original/include/linux/cpufreq.h linux/include/linux/cpufreq.h --- linux-original/include/linux/cpufreq.h 2003-11-20 19:17:28.695629048 +0100 +++ linux/include/linux/cpufreq.h 2003-11-20 19:17:34.314774808 +0100 @@ -57,7 +57,7 @@ struct cpufreq_cpuinfo { unsigned int max_freq; unsigned int min_freq; - unsigned int transition_latency; /* in 10^(-9) s */ + unsigned int transition_latency; /* in 10^(-9) s = nanoseconds */ }; struct cpufreq_real_policy {