Dominik Brodowski
2002-11-03T12:11:07Z

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[2.5. PATCH] cpufreq: update HyperThreading support in p4-clockmod.c driver

This patch updates the p4-clockmod.c driver to correctly manage
HyperThreading-enabled Pentium IVs as well as those models which do
not support HyperThreading - thanks to Venkatesh Pallipadi for
explaining cpu_sibling_map to me. Additionally, an EXPORT_SYMBOL
was missing. (spotted by Marc-Christian Petersen - thanks!)

Dominik

diff -ruN linux-2545original/arch/i386/kernel/cpu/cpufreq/p4-clockmod.c linux/arch/i386/kernel/cpu/cpufreq/p4-clockmod.c
--- linux-2545original/arch/i386/kernel/cpu/cpufreq/p4-clockmod.c Fri Nov 1 21:12:23 2002
+++ linux/arch/i386/kernel/cpu/cpufreq/p4-clockmod.c Sun Nov 3 12:30:34 2002
@@ -50,32 +50,55 @@
MODULE_PARM(stock_freq, "i");

static struct cpufreq_driver *cpufreq_p4_driver;
-static unsigned int cpufreq_p4_old_state = 0;

static int cpufreq_p4_setdc(unsigned int cpu, unsigned int newstate)
{
u32 l, h;
unsigned long cpus_allowed;
- struct cpufreq_freqs freqs;
+ struct cpufreq_freqs freqs;
+ int hyperthreading = 0;
+ int affected_cpu_map = 0;
+ int sibling = 0;

if (!cpu_online(cpu) || (newstate > DC_DISABLE) ||
(newstate == DC_RESV))
return -EINVAL;
- cpu = cpu >> 1; /* physical CPU #nr */
+
+ /* switch to physical CPU where state is to be changed*/
+ cpus_allowed = current->cpus_allowed;
+
+ /* only run on CPU to be set, or on its sibling */
+ affected_cpu_map = 1 << cpu;
+#ifdef CONFIG_X86_HT
+ hyperthreading = ((cpu_has_ht) && (smp_num_siblings == 2));
+ if (hyperthreading) {
+ sibling = cpu_sibling_map[cpu];
+ affected_cpu_map |= (1 << sibling);
+ }
+#endif
+ set_cpus_allowed(current, affected_cpu_map);
+ BUG_ON(!(smp_processor_id() & affected_cpu_map));
+
+ /* get current state */
+ rdmsr(MSR_IA32_THERM_CONTROL, l, h);
+ l = l >> 1;
+ l &= 0x7;
+
+ if (l == newstate) {
+ set_cpus_allowed(current, cpus_allowed);
+ return 0;
+ }

/* notifiers */
- freqs.old = stock_freq * cpufreq_p4_old_state / 8;
+ freqs.old = stock_freq * l / 8;
freqs.new = stock_freq * newstate / 8;
- freqs.cpu = 2*cpu;
- cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
- freqs.cpu++;
+ freqs.cpu = cpu;
cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
-
- /* switch to physical CPU where state is to be changed*/
- cpus_allowed = current->cpus_allowed;
- set_cpus_allowed(current, 3 << (2 * cpu));
- BUG_ON(cpu != (smp_processor_id() >> 1));
+ if (hyperthreading) {
+ freqs.cpu = sibling;
+ cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
+ }

rdmsr(MSR_IA32_THERM_STATUS, l, h);
if (l & 0x01)
@@ -86,10 +109,10 @@

rdmsr(MSR_IA32_THERM_CONTROL, l, h);
if (newstate == DC_DISABLE) {
- printk(KERN_INFO PFX "CPU#%d,%d disabling modulation\n", cpu, (cpu + 1));
+ printk(KERN_INFO PFX "CPU#%d disabling modulation\n", cpu);
wrmsr(MSR_IA32_THERM_CONTROL, l & ~(1<<4), h);
} else {
- printk(KERN_INFO PFX "CPU#%d,%d setting duty cycle to %d%%\n", cpu, (cpu + 1), ((125 * newstate) / 10));
+ printk(KERN_INFO PFX "CPU#%d setting duty cycle to %d%%\n", cpu, ((125 * newstate) / 10));
/* bits 63 - 5 : reserved
* bit 4 : enable/disable
* bits 3-1 : duty cycle
@@ -104,9 +127,10 @@

/* notifiers */
cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
- freqs.cpu--;
- cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
- cpufreq_p4_old_state = newstate;
+ if (hyperthreading) {
+ freqs.cpu = cpu;
+ cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
+ }

return 0;
}
@@ -123,7 +147,7 @@

if (policy->policy == CPUFREQ_POLICY_POWERSAVE)
{
- for (i=8; i>0; i++)
+ for (i=8; i>0; i--)
if ((policy->min <= ((stock_freq / 8) * i)) &&
(policy->max >= ((stock_freq / 8) * i)))
{
@@ -131,7 +155,7 @@
number_states++;
}
} else {
- for (i=0; i<=8; i--)
+ for (i=1; i<=8; i++)
if ((policy->min <= ((stock_freq / 8) * i)) &&
(policy->max >= ((stock_freq / 8) * i)))
{
@@ -143,9 +167,9 @@
/* if (number_states == 1) */
{
if (policy->cpu == CPUFREQ_ALL_CPUS) {
- for (i=0; i<(NR_CPUS/2); i++)
- if (cpu_online(2*i))
- cpufreq_p4_setdc((2*i), newstate);
+ for (i=0; i<NR_CPUS; i++)
+ if (cpu_online(i))
+ cpufreq_p4_setdc(i, newstate);
} else {
cpufreq_p4_setdc(policy->cpu, newstate);
}
@@ -235,7 +259,6 @@
for (i=0;i<NR_CPUS;i++)
driver->cpu_cur_freq[i] = stock_freq;
#endif
- cpufreq_p4_old_state = DC_DISABLE;

driver->verify = &cpufreq_p4_verify;
driver->setpolicy = &cpufreq_p4_setpolicy;
diff -ruN linux-2545original/arch/i386/kernel/i386_ksyms.c linux/arch/i386/kernel/i386_ksyms.c
--- linux-2545original/arch/i386/kernel/i386_ksyms.c Fri Nov 1 21:12:23 2002
+++ linux/arch/i386/kernel/i386_ksyms.c Fri Nov 1 21:08:44 2002
@@ -143,6 +143,11 @@
EXPORT_SYMBOL(mmx_copy_page);
#endif

+#ifdef CONFIG_X86_HT
+EXPORT_SYMBOL(smp_num_siblings);
+EXPORT_SYMBOL(cpu_sibling_map);
+#endif
+
#ifdef CONFIG_SMP
EXPORT_SYMBOL(cpu_data);
EXPORT_SYMBOL(cpu_online_map);

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