From: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@redhat.com>,
Vincent Guittot <vincent.guittot@linaro.org>,
Ricardo Neri <ricardo.neri@intel.com>,
"Ravi V. Shankar" <ravi.v.shankar@intel.com>,
Ben Segall <bsegall@google.com>,
Daniel Bristot de Oliveira <bristot@redhat.com>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Len Brown <len.brown@intel.com>, Mel Gorman <mgorman@suse.de>,
"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
Steven Rostedt <rostedt@goodmis.org>,
Tim Chen <tim.c.chen@linux.intel.com>,
Valentin Schneider <vschneid@redhat.com>,
x86@kernel.org, linux-kernel@vger.kernel.org,
"Tim C . Chen" <tim.c.chen@intel.com>
Subject: Re: [RFC PATCH 23/23] x86/process: Reset hardware history in context switch
Date: Thu, 6 Oct 2022 15:55:53 -0700 [thread overview]
Message-ID: <20221006225553.GB1624@ranerica-svr.sc.intel.com> (raw)
In-Reply-To: <Yz6TWL6zkD5Ee4/4@hirez.programming.kicks-ass.net>
On Thu, Oct 06, 2022 at 10:35:36AM +0200, Peter Zijlstra wrote:
> On Mon, Oct 03, 2022 at 04:07:58PM -0700, Ricardo Neri wrote:
> > On Tue, Sep 27, 2022 at 02:52:24PM +0200, Peter Zijlstra wrote:
> > > On Fri, Sep 09, 2022 at 04:12:05PM -0700, Ricardo Neri wrote:
> > >
> > > > +void reset_hardware_history(void)
> > > > +{
> > > > + if (!static_cpu_has(X86_FEATURE_HRESET))
> > > > + return;
> >
> > If I used cpu_feature_enabled(X86_FEATURE_ITD) along with the CONFIG_HFI_
> > THERMAL and its corresponding DISABLE_MASK bit the code below would be
> > compiled out.
>
> Nobody cares about compiled out -- distro's must enable all this.
I see.
> So
> what counts is the code size, and the alternative is smaller.
>
> > > > +
> > > > + asm volatile("mov %0, %%eax;" __ASM_HRESET "\n" : :
> > > > + "r" (hardware_history_features) : "%rax");
> > > > +}
> > >
> > > asm_inline volatile (ALTERNATIVE("", __ASM_HRESET, X86_FEATURE_HRESET)
> > > : : "a" (hardware_history_features) : "memory");
> >
> > Do you still prefer have implemented as an ALTERNATIVE?
>
> Yes, look at the generated code.
I did compare the sizes of the two options as several NOPs are added at
the end. I will take your code.
Thanks and BR,
Ricardo
next prev parent reply other threads:[~2022-10-06 22:49 UTC|newest]
Thread overview: 78+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-09 23:11 [RFC PATCH 00/23] sched: Introduce classes of tasks for load balance Ricardo Neri
2022-09-09 23:11 ` [RFC PATCH 01/23] sched/task_struct: Introduce classes of tasks Ricardo Neri
2022-09-14 13:46 ` Peter Zijlstra
2022-09-16 14:41 ` Ricardo Neri
2022-09-27 13:01 ` Peter Zijlstra
2022-10-02 22:32 ` Ricardo Neri
2022-09-09 23:11 ` [RFC PATCH 02/23] sched: Add interfaces for " Ricardo Neri
2022-09-09 23:11 ` [RFC PATCH 03/23] sched/core: Initialize the class of a new task Ricardo Neri
2022-09-26 14:57 ` Joel Fernandes
2022-09-26 21:53 ` Ricardo Neri
2022-09-27 13:04 ` Peter Zijlstra
2022-09-27 15:48 ` Joel Fernandes
2022-10-01 20:32 ` Ricardo Neri
2022-09-09 23:11 ` [RFC PATCH 04/23] sched/core: Add user_tick as argument to scheduler_tick() Ricardo Neri
2022-09-09 23:11 ` [RFC PATCH 05/23] sched/core: Move is_core_idle() out of fair.c Ricardo Neri
2022-09-09 23:11 ` [RFC PATCH 06/23] sched/core: Update the classification of the current task Ricardo Neri
2022-09-14 13:44 ` Peter Zijlstra
2022-09-16 14:42 ` Ricardo Neri
2022-09-09 23:11 ` [RFC PATCH 07/23] sched/fair: Collect load-balancing stats for task classes Ricardo Neri
2022-09-09 23:11 ` [RFC PATCH 08/23] sched/fair: Compute task-class performance scores for load balancing Ricardo Neri
2022-09-27 9:15 ` Peter Zijlstra
2022-10-26 3:57 ` Ricardo Neri
2022-10-26 8:55 ` Peter Zijlstra
2022-10-27 3:30 ` Ricardo Neri
2022-09-09 23:11 ` [RFC PATCH 09/23] sched/fair: Use task-class performance score to pick the busiest group Ricardo Neri
2022-09-27 11:01 ` Peter Zijlstra
2022-10-05 23:38 ` Ricardo Neri
2022-10-06 8:37 ` Peter Zijlstra
2022-10-06 19:07 ` Ricardo Neri
2022-09-09 23:11 ` [RFC PATCH 10/23] sched/fair: Use classes of tasks when selecting a busiest runqueue Ricardo Neri
2022-09-27 11:25 ` Peter Zijlstra
2022-10-07 23:36 ` Ricardo Neri
2022-09-09 23:11 ` [RFC PATCH 11/23] thermal: intel: hfi: Introduce Hardware Feedback Interface classes Ricardo Neri
2022-09-09 23:11 ` [RFC PATCH 12/23] thermal: intel: hfi: Convert table_lock to use flags-handling variants Ricardo Neri
2022-09-27 11:34 ` Peter Zijlstra
2022-09-27 11:36 ` Peter Zijlstra
2022-10-26 3:59 ` Ricardo Neri
2022-10-26 3:58 ` Ricardo Neri
2022-09-09 23:11 ` [RFC PATCH 13/23] x86/cpufeatures: Add the Intel Thread Director feature definitions Ricardo Neri
2022-09-09 23:11 ` [RFC PATCH 14/23] thermal: intel: hfi: Update the class of the current task Ricardo Neri
2022-09-27 11:46 ` Peter Zijlstra
2022-10-07 20:34 ` Ricardo Neri
2022-09-09 23:11 ` [RFC PATCH 15/23] thermal: intel: hfi: Report per-cpu class-specific performance scores Ricardo Neri
2022-09-27 11:59 ` Peter Zijlstra
2022-10-05 23:59 ` Ricardo Neri
2022-10-06 8:52 ` Peter Zijlstra
2022-10-06 9:14 ` Peter Zijlstra
2022-10-06 15:05 ` Brown, Len
2022-10-06 16:14 ` Peter Zijlstra
2022-10-07 11:20 ` Len Brown
2022-09-09 23:11 ` [RFC PATCH 16/23] thermal: intel: hfi: Define a default classification for unclassified tasks Ricardo Neri
2022-09-09 23:11 ` [RFC PATCH 17/23] thermal: intel: hfi: Enable the Intel Thread Director Ricardo Neri
2022-09-27 12:00 ` Peter Zijlstra
2022-10-06 1:50 ` Ricardo Neri
2022-09-09 23:12 ` [RFC PATCH 18/23] sched/task_struct: Add helpers for task classification Ricardo Neri
2022-09-27 11:52 ` Peter Zijlstra
2022-10-08 0:38 ` Ricardo Neri
2022-09-09 23:12 ` [RFC PATCH 19/23] sched/core: Initialize helpers of " Ricardo Neri
2022-09-09 23:12 ` [RFC PATCH 20/23] thermal: intel: hfi: Implement model-specific checks for " Ricardo Neri
2022-09-09 23:12 ` [RFC PATCH 21/23] x86/cpufeatures: Add feature bit for HRESET Ricardo Neri
2022-09-09 23:12 ` [RFC PATCH 22/23] x86/hreset: Configure history reset Ricardo Neri
2022-09-27 12:03 ` Peter Zijlstra
2022-10-02 22:34 ` Ricardo Neri
2022-09-09 23:12 ` [RFC PATCH 23/23] x86/process: Reset hardware history in context switch Ricardo Neri
2022-09-27 12:52 ` Peter Zijlstra
2022-10-03 23:07 ` Ricardo Neri
2022-10-06 8:35 ` Peter Zijlstra
2022-10-06 22:55 ` Ricardo Neri [this message]
2022-09-27 12:53 ` Peter Zijlstra
2022-10-02 22:02 ` Ricardo Neri
2022-09-27 13:15 ` Borislav Petkov
2022-10-02 22:12 ` Ricardo Neri
2022-10-02 22:15 ` Borislav Petkov
2022-10-03 19:49 ` Ricardo Neri
2022-10-03 19:55 ` Borislav Petkov
[not found] ` <20220910072120.2651-1-hdanton@sina.com>
2022-09-16 14:51 ` [RFC PATCH 06/23] sched/core: Update the classification of the current task Ricardo Neri
2022-10-11 19:12 ` Trying to apply patch set Carlos Bilbao
2022-10-18 2:31 ` Ricardo Neri
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