From: Steven Rostedt <rostedt@goodmis.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>,
x86@kernel.org, "Paul E. McKenney" <paulmck@kernel.org>,
Andy Lutomirski <luto@kernel.org>,
Alexandre Chartre <alexandre.chartre@oracle.com>,
Frederic Weisbecker <frederic@kernel.org>,
Paolo Bonzini <pbonzini@redhat.com>,
Sean Christopherson <sean.j.christopherson@intel.com>,
Masami Hiramatsu <mhiramat@kernel.org>,
Petr Mladek <pmladek@suse.com>,
Joel Fernandes <joel@joelfernandes.org>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Juergen Gross <jgross@suse.com>, Brian Gerst <brgerst@gmail.com>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Will Deacon <will@kernel.org>,
Tom Lendacky <thomas.lendacky@amd.com>,
Wei Liu <wei.liu@kernel.org>,
Michael Kelley <mikelley@microsoft.com>,
Jason Chen CJ <jason.cj.chen@intel.com>,
Zhao Yakui <yakui.zhao@intel.com>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>
Subject: Re: [patch V5 04/38] x86: Make hardware latency tracing explicit
Date: Thu, 14 May 2020 21:43:49 -0400 [thread overview]
Message-ID: <20200514214349.24642172@oasis.local.home> (raw)
In-Reply-To: <20200512213809.784331304@linutronix.de>
On Tue, 12 May 2020 23:01:03 +0200
Thomas Gleixner <tglx@linutronix.de> wrote:
> --- a/arch/x86/kernel/cpu/mce/core.c
> +++ b/arch/x86/kernel/cpu/mce/core.c
> @@ -1916,7 +1916,7 @@ static __always_inline void exc_machine_
> mce_check_crashing_cpu())
> return;
>
> - nmi_enter();
> + nmi_enter_notrace();
Now a machine check exception could happen and be a cause of latency
(although there may be more issues if it does). The "nmi_enter trace"
version does two things. One is for time measurements (if available),
and the other is just letting the hardware latency know it happen (a
simple increment).
The only thing that is checked is "smp_processor_id()" (I just
remembered it doesn't need per cpu, as it only runs on a single CPU at
a time).
Could the notrace version supply the increment, and leave the
trace_clock() in the trace version?
-- Steve
> /*
> * The call targets are marked noinstr, but objtool can't figure
> * that out because it's an indirect call. Annotate it.
>
next prev parent reply other threads:[~2020-05-15 1:43 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-12 21:00 [patch V5 00/38] x86/entry: Entry/exception code rework - the leftovers Thomas Gleixner
2020-05-12 21:01 ` [patch V5 01/38] x86/kvm/svm: Use uninstrumented wrmsrl() to restore GS Thomas Gleixner
2020-05-13 7:11 ` Jürgen Groß
2020-05-12 21:01 ` [patch V5 02/38] x86/entry/64: Use native swapgs in asm_native_load_gs_index() Thomas Gleixner
2020-05-13 2:02 ` Steven Rostedt
2020-05-13 6:34 ` Thomas Gleixner
2020-05-13 7:12 ` Jürgen Groß
2020-05-19 19:58 ` [tip: x86/entry] x86/entry/64: Use native swapgs in asm_load_gs_index() tip-bot2 for Thomas Gleixner
2020-05-12 21:01 ` [patch V5 03/38] nmi, tracing: Provide nmi_enter/exit_notrace() Thomas Gleixner
2020-05-15 1:32 ` Steven Rostedt
2020-05-15 1:35 ` Steven Rostedt
2020-05-15 1:37 ` Steven Rostedt
2020-05-12 21:01 ` [patch V5 04/38] x86: Make hardware latency tracing explicit Thomas Gleixner
2020-05-15 1:43 ` Steven Rostedt [this message]
2020-05-15 15:08 ` Thomas Gleixner
2020-05-12 21:01 ` [patch V5 05/38] genirq: Provide irq_enter/exit_rcu() Thomas Gleixner
2020-05-12 21:01 ` [patch V5 06/38] x86/entry: Provide helpers for execute on irqstack Thomas Gleixner
2020-05-13 21:43 ` Josh Poimboeuf
2020-05-12 21:01 ` [patch V5 07/38] x86/entry/64: Move do_softirq_own_stack() to C Thomas Gleixner
2020-05-12 21:01 ` [patch V5 08/38] x86/entry: Split idtentry_enter/exit() Thomas Gleixner
2020-05-12 21:01 ` [patch V5 09/38] x86/entry: Switch XEN/PV hypercall entry to IDTENTRY Thomas Gleixner
2020-05-14 16:24 ` Boris Ostrovsky
2020-05-12 21:01 ` [patch V5 10/38] x86/entry/64: Simplify idtentry_body Thomas Gleixner
2020-05-12 21:01 ` [patch V5 11/38] rcu: Provide __rcu_is_watching() Thomas Gleixner
2020-05-19 19:52 ` [tip: core/rcu] " tip-bot2 for Thomas Gleixner
2020-05-12 21:01 ` [patch V5 12/38] x86/entry: Provide idtentry_entry/exit_cond_rcu() Thomas Gleixner
2020-05-12 21:01 ` [patch V5 13/38] x86/entry: Switch page fault exception to IDTENTRY_RAW Thomas Gleixner
2020-05-12 21:01 ` [patch V5 14/38] x86/entry: Remove the transition leftovers Thomas Gleixner
2020-05-12 21:01 ` [patch V5 15/38] x86/entry: Change exit path of xen_failsafe_callback Thomas Gleixner
2020-05-12 21:01 ` [patch V5 16/38] x86/entry/64: Remove error_exit Thomas Gleixner
2020-05-12 21:01 ` [patch V5 17/38] x86/entry/32: Remove common_exception Thomas Gleixner
2020-05-12 21:01 ` [patch V5 18/38] x86/irq: Use generic irq_regs implementation Thomas Gleixner
2020-05-12 21:01 ` [patch V5 19/38] x86/irq: Convey vector as argument and not in ptregs Thomas Gleixner
2020-05-12 21:01 ` [patch V5 20/38] x86/irq/64: Provide handle_irq() Thomas Gleixner
2020-05-12 21:01 ` [patch V5 21/38] x86/entry: Add IRQENTRY_IRQ macro Thomas Gleixner
2020-05-12 21:01 ` [patch V5 22/38] x86/entry: Use idtentry for interrupts Thomas Gleixner
2020-05-12 21:01 ` [patch V5 23/38] genirq: Provde __irq_enter/exit_raw() Thomas Gleixner
2020-05-12 21:01 ` [patch V5 24/38] x86/entry: Provide IDTENTRY_SYSVEC Thomas Gleixner
2020-05-15 0:16 ` Boris Ostrovsky
2020-05-15 8:52 ` Thomas Gleixner
2020-05-12 21:01 ` [patch V5 25/38] x86/entry: Convert APIC interrupts to IDTENTRY_SYSVEC Thomas Gleixner
2020-05-12 21:01 ` [patch V5 26/38] x86/entry: Convert SMP system vectors " Thomas Gleixner
2020-05-12 21:01 ` [patch V5 27/38] x86/entry: Convert various system vectors Thomas Gleixner
2020-05-12 21:01 ` [patch V5 28/38] x86/entry: Convert KVM vectors to IDTENTRY_SYSVEC Thomas Gleixner
2020-05-12 21:01 ` [patch V5 29/38] x86/entry: Convert various hypervisor " Thomas Gleixner
2020-05-12 21:01 ` [patch V5 30/38] x86/entry: Convert XEN hypercall vector " Thomas Gleixner
2020-05-12 21:01 ` [patch V5 31/38] x86/entry: Convert reschedule interrupt to IDTENTRY_SYSVEC_SIMPLE Thomas Gleixner
2020-05-12 21:01 ` [patch V5 32/38] x86/entry: Remove the apic/BUILD interrupt leftovers Thomas Gleixner
2020-05-12 21:01 ` [patch V5 33/38] x86/entry/64: Remove IRQ stack switching ASM Thomas Gleixner
2020-05-12 21:01 ` [patch V5 34/38] x86/entry: Make enter_from_user_mode() static Thomas Gleixner
2020-05-12 21:01 ` [patch V5 35/38] x86/entry/32: Remove redundant irq disable code Thomas Gleixner
2020-05-12 21:01 ` [patch V5 36/38] x86/entry/64: Remove TRACE_IRQS_*_DEBUG Thomas Gleixner
2020-05-12 21:01 ` [patch V5 37/38] x86/entry: Move paranoid irq tracing out of ASM code Thomas Gleixner
2020-05-12 21:01 ` [patch V5 38/38] x86/entry: Remove the TRACE_IRQS cruft Thomas Gleixner
2020-05-14 16:35 ` [patch V5 00/38] x86/entry: Entry/exception code rework - the leftovers Paul E. McKenney
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