Move xen patchset to new version's subdir.

[people/pmueller/ipfire-2.x.git] / src / patches / suse-2.6.27.31 / patches.fixes / cpufreq_ondemand_performance_optimise_default_settings.patch

diff --git a/src/patches/suse-2.6.27.31/patches.fixes/cpufreq_ondemand_performance_optimise_default_settings.patch b/src/patches/suse-2.6.27.31/patches.fixes/cpufreq_ondemand_performance_optimise_default_settings.patch
new file mode 100644 (file)
index 0000000..1c5b806
--- /dev/null
+++ b/src/patches/suse-2.6.27.31/patches.fixes/cpufreq_ondemand_performance_optimise_default_settings.patch
@@ -0,0 +1,67 @@
+From: Thomas Renninger <trenn@suse.de>
+Subject: CPUFREQ: ondemand: Limit default sampling rate to 300ms max.
+References: bnc#464461
+Patch-Mainline: never, SLE11 only
+
+HW cpufreq drivers (e.g. all non-acpi AMD) may report too high latency values.
+The default sampling rate (how often the ondemand/conservative governor
+checks for frequency adjustments) may therefore be much too high,
+resulting in performance loss.
+
+Restrict default sampling rate to 300ms. 333ms sampling rate is field
+tested with userspace governors, 300ms should be a fine maximum default
+value for the ondemand kernel governor for all HW out there.
+
+Set default up_threshold to 40 on multi core systems.
+This should avoid effects where two CPU intensive threads are waiting on
+each other on separate cores. On a single core machine these would all be
+processed on one core resulting in higher utilization of the one core.
+
+---
+ drivers/cpufreq/cpufreq_ondemand.c |   26 ++++++++++++++++++++++++++
+ 1 file changed, 26 insertions(+)
+
+Index: linux-2.6.27/drivers/cpufreq/cpufreq_ondemand.c
+===================================================================
+--- linux-2.6.27.orig/drivers/cpufreq/cpufreq_ondemand.c
++++ linux-2.6.27/drivers/cpufreq/cpufreq_ondemand.c
+@@ -58,6 +58,7 @@ static unsigned int def_sampling_rate;
+ #define MAX_SAMPLING_RATE                     (500 * def_sampling_rate)
+ #define DEF_SAMPLING_RATE_LATENCY_MULTIPLIER  (1000)
+ #define TRANSITION_LATENCY_LIMIT              (10 * 1000 * 1000)
++#define MAX_DEFAULT_SAMPLING_RATE             (300 * 1000)
+ 
+ static void do_dbs_timer(struct work_struct *work);
+ 
+@@ -558,6 +559,31 @@ static int cpufreq_governor_dbs(struct c
+                       if (def_sampling_rate < MIN_STAT_SAMPLING_RATE)
+                               def_sampling_rate = MIN_STAT_SAMPLING_RATE;
+ 
++                      /* 
++                       * Cut def_sampling rate to 300ms if it was above,
++                       * still consider to not set it above latency
++                       * transition * 100
++                       */
++                      if (def_sampling_rate > MAX_DEFAULT_SAMPLING_RATE) {
++                              def_sampling_rate =
++                                      (MAX_DEFAULT_SAMPLING_RATE < MINIMUM_SAMPLING_RATE)
++                                      ? MINIMUM_SAMPLING_RATE : MAX_DEFAULT_SAMPLING_RATE;
++                              printk(KERN_INFO "CPUFREQ: ondemand sampling "
++                                     "rate set to %d ms\n",
++                                     def_sampling_rate / 1000);
++                      }
++                      /*
++                       * Be conservative in respect to performance.
++                       * If an application calculates using two threads
++                       * depending on each other, they will be run on several
++                       * CPU cores resulting on 50% load on both.
++                       * SLED might still want to prefer 80% up_threshold
++                       * by default, but we cannot differ that here.
++                       */
++                      if (num_online_cpus() > 1)
++                              dbs_tuners_ins.up_threshold =
++                                      DEF_FREQUENCY_UP_THRESHOLD / 2;
++
+                       dbs_tuners_ins.sampling_rate = def_sampling_rate;
+               }
+               dbs_timer_init(this_dbs_info);