From: Peter Zijlstra <peterz@infradead.org>
To: Andi Kleen <andi@firstfloor.org>
Cc: acme@kernel.org, jolsa@kernel.org, linux-kernel@vger.kernel.org,
Andi Kleen <ak@linux.intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
x86@kernel.org
Subject: Re: [PATCH 01/10] x86: Add topology_max_smt_threads()
Date: Fri, 6 May 2016 12:13:18 +0200 [thread overview]
Message-ID: <20160506101318.GV3430@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <1462489447-31832-2-git-send-email-andi@firstfloor.org>
It might help if you actually Cc'd tglx and x86 in general.
On Thu, May 05, 2016 at 04:03:58PM -0700, Andi Kleen wrote:
> From: Andi Kleen <ak@linux.intel.com>
>
> 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.
>
> Signed-off-by: Andi Kleen <ak@linux.intel.com>
> ---
> arch/x86/include/asm/topology.h | 5 +++++
> arch/x86/kernel/smpboot.c | 24 ++++++++++++++++++++++++
> 2 files changed, 29 insertions(+)
>
> diff --git a/arch/x86/include/asm/topology.h b/arch/x86/include/asm/topology.h
> index 7f991bd5031b..4707555f209e 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..6e5a721857f5 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;
> @@ -489,6 +492,7 @@ void set_cpu_sibling_map(int cpu)
> struct cpuinfo_x86 *c = &cpu_data(cpu);
> struct cpuinfo_x86 *o;
> int i;
> + int threads;
>
> cpumask_set_cpu(cpu, cpu_sibling_setup_mask);
>
> @@ -545,6 +549,10 @@ 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 +1444,21 @@ __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;
> + int 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 +1483,7 @@ 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)
> --
> 2.5.5
>
next prev parent reply other threads:[~2016-05-06 10:13 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 [this message]
2016-05-06 10:47 ` Thomas Gleixner
2016-05-06 17:24 ` [UPDATED PATCH " Andi Kleen
2016-05-07 8:11 ` 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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20160506101318.GV3430@twins.programming.kicks-ass.net \
--to=peterz@infradead.org \
--cc=acme@kernel.org \
--cc=ak@linux.intel.com \
--cc=andi@firstfloor.org \
--cc=jolsa@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=tglx@linutronix.de \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).