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From: Peter Zijlstra <peterz@infradead.org>
To: Nadav Amit <nadav.amit@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>,
	the arch/x86 maintainers <x86@kernel.org>,
	Andy Lutomirski <luto@kernel.org>,
	"H. Peter Anvin" <hpa@zytor.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>
Subject: Re: [PATCH] x86: Align TLB invalidation info
Date: Thu, 1 Feb 2018 10:38:47 +0100	[thread overview]
Message-ID: <20180201093847.GZ2269@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <DBF48795-2F4B-4C65-A5DD-A78D2214DF9B@gmail.com>

On Wed, Jan 31, 2018 at 09:38:46PM -0800, Nadav Amit wrote:

> I used ftrace to measure the execution time of flush_tlb_func_remote() on a
> 2-socket Haswell machine, using a microbenchmark I wrote for some research
> project.

However cool ftrace is, it is _really_ bad for such uses. The cost of
using ftrace is many many time higher than any change you could affect
by this.

A microbench and/or perf is what you should use for this.

  reply	other threads:[~2018-02-01  9:39 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-31 20:11 [PATCH] x86: Align TLB invalidation info Nadav Amit
2018-01-31 20:24 ` Andy Lutomirski
2018-01-31 20:48   ` Nadav Amit
2018-01-31 20:49     ` Dave Hansen
2018-01-31 20:52       ` Nadav Amit
2018-01-31 21:00     ` Andy Lutomirski
2018-01-31 21:01 ` Dave Hansen
2018-01-31 21:09   ` Nadav Amit
2018-01-31 21:15     ` Andy Lutomirski
2018-01-31 21:17       ` Nadav Amit
     [not found]     ` <f7270e0d-d1d1-599d-d2c9-ddc2c263e090@linux.intel.com>
2018-02-01  5:38       ` Nadav Amit
2018-02-01  9:38         ` Peter Zijlstra [this message]
2018-02-01 18:45           ` Nadav Amit

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