starlingx/integ
Code Issues Proposed changes
76cfa48701
integ/kernel/kernel-rt/centos/patches/timer-Minimize-nohz-off-overhead.patch
Scott Little bab9bb6b69 Internal restructuring of stx-integ 
Create new directories:
   ceph
   config
   config-files
   filesystem
   kernel
   kernel/kernel-modules
   ldap
   logging
   strorage-drivers
   tools
   utilities
   virt

Retire directories:
   connectivity
   core
   devtools
   support
   extended

Delete two packages:
   tgt
   irqbalance

Relocated packages:
   base/
      dhcp
      initscripts
      libevent
      lighttpd
      linuxptp
      memcached
      net-snmp
      novnc
      ntp
      openssh
      pam
      procps
      sanlock
      shadow
      sudo
      systemd
      util-linux
      vim
      watchdog

   ceph/
      python-cephclient

   config/
      facter
      puppet-4.8.2
      puppet-modules

   filesystem/
      e2fsprogs
      nfs-utils
      nfscheck

   kernel/
      kernel-std
      kernel-rt

   kernel/kernel-modules/
      mlnx-ofa_kernel

   ldap/
      nss-pam-ldapd
      openldap

   logging/
      syslog-ng
      logrotate

   networking/
      lldpd
      iproute
      mellanox
      python-ryu
      mlx4-config

   python/
      python-2.7.5
      python-django
      python-gunicorn
      python-setuptools
      python-smartpm
      python-voluptuous

   security/
      shim-signed
      shim-unsigned
      tboot

   strorage-drivers/
      python-3parclient
      python-lefthandclient

   virt/
      cloud-init
      libvirt
      libvirt-python
      qemu

   tools/
      storage-topology
      vm-topology

   utilities/
      tis-extensions
      namespace-utils
      nova-utils
      update-motd

Change-Id: I37ade764d873c701b35eac5881eb40412ba64a86
Story: 2002801
Task: 22687
Signed-off-by: Scott Little <scott.little@windriver.com>
2018-08-01 10:06:31 -04:00

169 lines
6.0 KiB
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From ecfd98039a9be52230746b209010c77adb575629 Mon Sep 17 00:00:00 2001
Message-Id: <ecfd98039a9be52230746b209010c77adb575629.1528226387.git.Jim.Somerville@windriver.com>
In-Reply-To: <c8270e79f6b7008fde44b8d5aa6314d8cf89d3ed.1528226387.git.Jim.Somerville@windriver.com>
References: <c8270e79f6b7008fde44b8d5aa6314d8cf89d3ed.1528226387.git.Jim.Somerville@windriver.com>
From: Thomas Gleixner <tglx@linutronix.de>
Date: Tue, 26 May 2015 22:50:35 +0000
Subject: [PATCH 28/32] timer: Minimize nohz off overhead
If nohz is disabled on the kernel command line the [hr]timer code
still calls wake_up_nohz_cpu() and tick_nohz_full_cpu(), a pretty
pointless exercise. Cache nohz_active in [hr]timer per cpu bases and
avoid the overhead.
Before:
48.10% hog [.] main
15.25% [kernel] [k] _raw_spin_lock_irqsave
9.76% [kernel] [k] _raw_spin_unlock_irqrestore
6.50% [kernel] [k] mod_timer
6.44% [kernel] [k] lock_timer_base.isra.38
3.87% [kernel] [k] detach_if_pending
3.80% [kernel] [k] del_timer
2.67% [kernel] [k] internal_add_timer
1.33% [kernel] [k] __internal_add_timer
0.73% [kernel] [k] timerfn
0.54% [kernel] [k] wake_up_nohz_cpu
After:
48.73% hog [.] main
15.36% [kernel] [k] _raw_spin_lock_irqsave
9.77% [kernel] [k] _raw_spin_unlock_irqrestore
6.61% [kernel] [k] lock_timer_base.isra.38
6.42% [kernel] [k] mod_timer
3.90% [kernel] [k] detach_if_pending
3.76% [kernel] [k] del_timer
2.41% [kernel] [k] internal_add_timer
1.39% [kernel] [k] __internal_add_timer
0.76% [kernel] [k] timerfn
We probably should have a cached value for nohz full in the per cpu
bases as well to avoid the cpumask check. The base cache line is hot
already, the cpumask not necessarily.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Joonwoo Park <joonwoop@codeaurora.org>
Cc: Wenbo Wang <wenbo.wang@memblaze.com>
Link: http://lkml.kernel.org/r/20150526224512.207378134@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Alex Kozyrev <alex.kozyrev@windriver.com>
Signed-off-by: Jim Somerville <Jim.Somerville@windriver.com>
---
include/linux/hrtimer.h | 2 ++
kernel/time/tick-internal.h | 4 ++--
kernel/time/tick-sched.c | 2 +-
kernel/timer.c | 14 +++++++++++---
4 files changed, 16 insertions(+), 6 deletions(-)
diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h
index 00d4c9b..6183bf8 100644
--- a/include/linux/hrtimer.h
+++ b/include/linux/hrtimer.h
@@ -176,6 +176,7 @@ enum hrtimer_base_type {
* Note that in RHEL7 clock_was_set is upstream's
* clock_was_set_seq (KABI).
* @migration_enabled: The migration of hrtimers to other cpus is enabled
+ * @nohz_active: The nohz functionality is enabled
* @expires_next: absolute time of the next event which was scheduled
* via clock_set_next_event()
* @hres_active: State of high resolution mode
@@ -191,6 +192,7 @@ struct hrtimer_cpu_base {
unsigned int active_bases;
unsigned int clock_was_set; /* clock_was_set_seq */
bool migration_enabled;
+ bool nohz_active;
#ifdef CONFIG_HIGH_RES_TIMERS
ktime_t expires_next;
int hres_active;
diff --git a/kernel/time/tick-internal.h b/kernel/time/tick-internal.h
index 3ebdda4..13468bd 100644
--- a/kernel/time/tick-internal.h
+++ b/kernel/time/tick-internal.h
@@ -173,9 +173,9 @@ extern unsigned long tick_nohz_active;
#endif
#if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
-extern void timers_update_migration(void);
+extern void timers_update_migration(bool update_nohz);
#else
-static inline void timers_update_migration(void) { }
+static inline void timers_update_migration(bool update_nohz) { }
#endif
DECLARE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases);
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 6c92920..3ccc18c 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -980,7 +980,7 @@ static inline void tick_nohz_activate(struct tick_sched *ts, int mode)
ts->nohz_mode = mode;
/* One update is enough */
if (!test_and_set_bit(0, &tick_nohz_active))
- timers_update_migration();
+ timers_update_migration(true);
}
/**
diff --git a/kernel/timer.c b/kernel/timer.c
index 4fcb630..08c96e1 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -88,6 +88,7 @@ struct tvec_base {
unsigned long active_timers;
int cpu;
bool migration_enabled;
+ bool nohz_active;
struct tvec_root tv1;
struct tvec tv2;
struct tvec tv3;
@@ -103,7 +104,7 @@ static DEFINE_PER_CPU(struct tvec_base *, tvec_bases) = &boot_tvec_bases;
#if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
unsigned int sysctl_timer_migration = 1;
-void timers_update_migration(void)
+void timers_update_migration(bool update_nohz)
{
bool on = sysctl_timer_migration && tick_nohz_active;
unsigned int cpu;
@@ -119,6 +120,10 @@ void timers_update_migration(void)
tvec_base->migration_enabled = on;
hrtimer_base = &per_cpu(hrtimer_bases, cpu);
hrtimer_base->migration_enabled = on;
+ if (!update_nohz)
+ continue;
+ tvec_base->nohz_active = true;
+ hrtimer_base->nohz_active = true;
}
}
@@ -132,7 +137,7 @@ int timer_migration_handler(struct ctl_table *table, int write,
mutex_lock(&mutex);
ret = proc_dointvec(table, write, buffer, lenp, ppos);
if (!ret && write)
- timers_update_migration();
+ timers_update_migration(false);
mutex_unlock(&mutex);
return ret;
}
@@ -482,8 +487,11 @@ static void internal_add_timer(struct tvec_base *base, struct timer_list *timer)
* require special care against races with idle_cpu(), lets deal
* with that later.
*/
- if (!tbase_get_deferrable(base) || tick_nohz_full_cpu(base->cpu))
+ if (base->nohz_active) {
+ if (!tbase_get_deferrable(base) ||
+ tick_nohz_full_cpu(base->cpu))
wake_up_nohz_cpu(base->cpu);
+ }
}
#ifdef CONFIG_TIMER_STATS
--
1.8.3.1
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