[Xen-changelog] [xen-unstable] x86, cpufreq: fix ondemand governor to take aperf/mperf feedback

[Xen patchbot-unstable <patchbot-unstable@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1242693086 -3600
# Node ID 674e4d43955f594e1677be50dd18e3e8beb72dd7
# Parent  b5522741f6b5ad0bbc5f46462ae4aac33ee8bb87
x86, cpufreq: fix ondemand governor to take aperf/mperf feedback

APERF/MPERF MSRs provides feedback about actual freq in
eplased time, which could be different from requested freq by
governor. However currently ondemand governor only takes that
feedback at freq down path. We should do that for scale up too.

Signed-off-by: Liu, Jinsong <jinsong.liu@xxxxxxxxx>
---
 xen/drivers/cpufreq/cpufreq_ondemand.c |   43 ++++++++++++++++-----------------
 1 files changed, 22 insertions(+), 21 deletions(-)

diff -r b5522741f6b5 -r 674e4d43955f xen/drivers/cpufreq/cpufreq_ondemand.c
--- a/xen/drivers/cpufreq/cpufreq_ondemand.c    Tue May 19 01:27:36 2009 +0100
+++ b/xen/drivers/cpufreq/cpufreq_ondemand.c    Tue May 19 01:31:26 2009 +0100
@@ -97,9 +97,8 @@ int get_cpufreq_ondemand_para(uint32_t *
 
 static void dbs_check_cpu(struct cpu_dbs_info_s *this_dbs_info)
 {
-    unsigned int load = 0;
-    uint64_t cur_ns, idle_ns, total_ns;
-
+    uint64_t cur_ns, total_ns;
+    uint64_t max_load_freq = 0;
     struct cpufreq_policy *policy;
     unsigned int j;
 
@@ -121,30 +120,34 @@ static void dbs_check_cpu(struct cpu_dbs
         return;
 
     /* Get Idle Time */
-    idle_ns = UINT_MAX;
     for_each_cpu_mask(j, policy->cpus) {
-        uint64_t total_idle_ns;
-        unsigned int tmp_idle_ns;
+        uint64_t idle_ns, total_idle_ns;
+        uint64_t load, load_freq, freq_avg;
         struct cpu_dbs_info_s *j_dbs_info;
 
         j_dbs_info = &per_cpu(cpu_dbs_info, j);
         total_idle_ns = get_cpu_idle_time(j);
-        tmp_idle_ns = total_idle_ns - j_dbs_info->prev_cpu_idle;
+        idle_ns = total_idle_ns - j_dbs_info->prev_cpu_idle;
         j_dbs_info->prev_cpu_idle = total_idle_ns;
 
-        if (tmp_idle_ns < idle_ns)
-            idle_ns = tmp_idle_ns;
-    }
-
-    if (likely(total_ns > idle_ns))
-        load = (100 * (total_ns - idle_ns)) / total_ns;
+        if (unlikely(total_ns < idle_ns))
+            continue;
+
+        load = 100 * (total_ns - idle_ns) / total_ns;
+
+        freq_avg = cpufreq_driver_getavg(j, GOV_GETAVG);
+
+        load_freq = load * freq_avg;
+        if (load_freq > max_load_freq)
+            max_load_freq = load_freq;
+    }
 
     /* Check for frequency increase */
-    if (load > dbs_tuners_ins.up_threshold) {
+    if (max_load_freq > dbs_tuners_ins.up_threshold * policy->cur) {
         /* if we are already at full speed then break out early */
         if (policy->cur == policy->max)
             return;
-        __cpufreq_driver_target(policy, policy->max,CPUFREQ_RELATION_H);
+        __cpufreq_driver_target(policy, policy->max, CPUFREQ_RELATION_H);
         return;
     }
 
@@ -158,12 +161,10 @@ static void dbs_check_cpu(struct cpu_dbs
      * can support the current CPU usage without triggering the up
      * policy. To be safe, we focus 10 points under the threshold.
      */
-    if (load < (dbs_tuners_ins.up_threshold - 10)) {
-        unsigned int freq_next, freq_cur;
-
-        freq_cur = cpufreq_driver_getavg(policy->cpu, GOV_GETAVG);
-
-        freq_next = (freq_cur * load) / (dbs_tuners_ins.up_threshold - 10);
+    if (max_load_freq < (dbs_tuners_ins.up_threshold - 10) * policy->cur) {
+        uint64_t freq_next;
+
+        freq_next = max_load_freq / (dbs_tuners_ins.up_threshold - 10);
 
         __cpufreq_driver_target(policy, freq_next, CPUFREQ_RELATION_L);
     }

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