From: Andi Kleen <andi@firstfloor.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>,
Andi Kleen <andi@firstfloor.org>,
acme@kernel.org, jolsa@kernel.org, linux-kernel@vger.kernel.org,
Andi Kleen <ak@linux.intel.com>,
x86@kernel.org
Subject: [UPDATED PATCH 01/10] x86: Add topology_max_smt_threads()
Date: Fri, 6 May 2016 10:24:26 -0700 [thread overview]
Message-ID: <20160506172426.GW13997@two.firstfloor.org> (raw)
In-Reply-To: <alpine.DEB.2.11.1605061243420.3540@nanos>
For SMT specific workarounds it is useful to know if SMT is active
on any online CPU in the system. This currently requires a loop
over all online CPUs.
Add a global variable that is updated with the maximum number
of smt threads on any CPU on online/offline, and use it for
topology_max_smt_threads()
The single call is easier to use than a loop.
Not exported to user space because user space already can use
the existing sibling interfaces to find this out.
v2: Code formatting changes and use __ for variable name
Cc: tglx@linutronix.de
Signed-off-by: Andi Kleen <ak@linux.intel.com>
diff --git a/arch/x86/include/asm/topology.h b/arch/x86/include/asm/topology.h
index 7f991bd5031b..f79181c03561 100644
--- a/arch/x86/include/asm/topology.h
+++ b/arch/x86/include/asm/topology.h
@@ -129,6 +129,10 @@ extern const struct cpumask *cpu_coregroup_mask(int cpu);
extern unsigned int __max_logical_packages;
#define topology_max_packages() (__max_logical_packages)
+
+extern int __max_smt_threads;
+#define topology_max_smt_threads() __max_smt_threads
+
int topology_update_package_map(unsigned int apicid, unsigned int cpu);
extern int topology_phys_to_logical_pkg(unsigned int pkg);
#else
@@ -136,6 +140,7 @@ extern int topology_phys_to_logical_pkg(unsigned int pkg);
static inline int
topology_update_package_map(unsigned int apicid, unsigned int cpu) { return 0; }
static inline int topology_phys_to_logical_pkg(unsigned int pkg) { return 0; }
+#define topology_max_smt_threads() 1
#endif
static inline void arch_fix_phys_package_id(int num, u32 slot)
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index a2065d3b3b39..76bf9d855ee3 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -105,6 +105,9 @@ static unsigned int max_physical_pkg_id __read_mostly;
unsigned int __max_logical_packages __read_mostly;
EXPORT_SYMBOL(__max_logical_packages);
+/* Maximum number of SMT threads on any online core */
+int __max_smt_threads __read_mostly;
+
static inline void smpboot_setup_warm_reset_vector(unsigned long start_eip)
{
unsigned long flags;
@@ -488,7 +491,7 @@ void set_cpu_sibling_map(int cpu)
bool has_mp = has_smt || boot_cpu_data.x86_max_cores > 1;
struct cpuinfo_x86 *c = &cpu_data(cpu);
struct cpuinfo_x86 *o;
- int i;
+ int i, threads;
cpumask_set_cpu(cpu, cpu_sibling_setup_mask);
@@ -545,6 +548,10 @@ void set_cpu_sibling_map(int cpu)
if (match_die(c, o) && !topology_same_node(c, o))
primarily_use_numa_for_topology();
}
+
+ threads = cpumask_weight(topology_sibling_cpumask(cpu));
+ if (threads > __max_smt_threads)
+ __max_smt_threads = threads;
}
/* maps the cpu to the sched domain representing multi-core */
@@ -1436,6 +1443,21 @@ __init void prefill_possible_map(void)
#ifdef CONFIG_HOTPLUG_CPU
+/* Recompute SMT state for all CPUs on offline */
+static void recompute_smt_state(void)
+{
+ int max_threads, cpu;
+
+ max_threads = 0;
+ for_each_online_cpu (cpu) {
+ int threads = cpumask_weight(topology_sibling_cpumask(cpu));
+
+ if (threads > max_threads)
+ max_threads = threads;
+ }
+ __max_smt_threads = max_threads;
+}
+
static void remove_siblinginfo(int cpu)
{
int sibling;
@@ -1460,6 +1482,7 @@ static void remove_siblinginfo(int cpu)
c->phys_proc_id = 0;
c->cpu_core_id = 0;
cpumask_clear_cpu(cpu, cpu_sibling_setup_mask);
+ recompute_smt_state();
}
static void remove_cpu_from_maps(int cpu)
next prev parent reply other threads:[~2016-05-06 17:24 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-05 23:03 Add top down metrics to perf stat Andi Kleen
2016-05-05 23:03 ` [PATCH 01/10] x86: Add topology_max_smt_threads() Andi Kleen
2016-05-06 10:13 ` Peter Zijlstra
2016-05-06 10:47 ` Thomas Gleixner
2016-05-06 17:24 ` Andi Kleen [this message]
2016-05-07 8:11 ` [UPDATED PATCH " Thomas Gleixner
2016-05-12 8:07 ` Ingo Molnar
2016-05-05 23:03 ` [PATCH 02/10] x86, perf: Support sysfs files depending on SMT status Andi Kleen
2016-05-09 9:42 ` Peter Zijlstra
2016-05-09 14:27 ` Andi Kleen
2016-05-09 14:34 ` Peter Zijlstra
2016-05-12 8:05 ` Ingo Molnar
2016-05-05 23:04 ` [PATCH 03/10] x86, perf: Add Top Down events to Intel Core Andi Kleen
2016-05-11 13:23 ` Jiri Olsa
2016-05-11 13:29 ` Peter Zijlstra
2016-05-12 8:10 ` Ingo Molnar
2016-05-05 23:04 ` [PATCH 04/10] x86, perf: Add Top Down events to Intel Atom Andi Kleen
2016-05-05 23:04 ` [PATCH 05/10] x86, perf: Use new topology_max_smt_threads() in HT leak workaround Andi Kleen
2016-05-05 23:04 ` [PATCH 06/10] perf, tools, stat: Avoid fractional digits for integer scales Andi Kleen
2016-05-07 19:10 ` Jiri Olsa
2016-05-07 19:24 ` Andi Kleen
2016-05-11 13:00 ` Jiri Olsa
2016-05-11 16:43 ` Arnaldo Carvalho de Melo
2016-05-20 6:42 ` [tip:perf/urgent] perf " tip-bot for Andi Kleen
2016-05-05 23:04 ` [PATCH 07/10] perf, tools, stat: Scale values by unit before metrics Andi Kleen
2016-05-07 19:14 ` Jiri Olsa
2016-05-10 20:30 ` [tip:perf/core] perf " tip-bot for Andi Kleen
2016-05-05 23:04 ` [PATCH 08/10] perf, tools, stat: Basic support for TopDown in perf stat Andi Kleen
2016-05-05 23:04 ` [PATCH 09/10] perf, tools, stat: Add computation of TopDown formulas Andi Kleen
2016-05-05 23:04 ` [PATCH 10/10] perf, tools, stat: Add extra output of counter values with -vv Andi Kleen
2016-05-12 8:03 ` Jiri Olsa
2016-05-20 0:05 ` Andi Kleen
2016-05-12 7:47 ` Add top down metrics to perf stat Jiri Olsa
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