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From: Steven Rostedt <rostedt@goodmis.org>
To: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>,
	Andy Lutomirski <luto@kernel.org>, Ingo Molnar <mingo@kernel.org>,
	LKML <linux-kernel@vger.kernel.org>, X86 ML <x86@kernel.org>,
	Ard Biesheuvel <ard.biesheuvel@linaro.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	Jason Baron <jbaron@akamai.com>, Jiri Kosina <jkosina@suse.cz>,
	David Laight <David.Laight@aculab.com>,
	Borislav Petkov <bp@alien8.de>
Subject: Re: [PATCH RFC 0/3] Static calls
Date: Fri, 9 Nov 2018 14:59:18 -0500	[thread overview]
Message-ID: <20181109145918.28df6616@gandalf.local.home> (raw)
In-Reply-To: <20181109194409.mnrzdee6gh4ujutm@treble>

On Fri, 9 Nov 2018 13:44:09 -0600
Josh Poimboeuf <jpoimboe@redhat.com> wrote:

> On Fri, Nov 09, 2018 at 02:37:03PM -0500, Steven Rostedt wrote:
> > On Fri, 9 Nov 2018 11:05:51 -0800
> > Andy Lutomirski <luto@amacapital.net> wrote:
> >   
> > > > Not sure what Andy was talking about, but I'm currently implementing
> > > > tracepoints to use this, as tracepoints use indirect calls, and are a
> > > > prime candidate for static calls, as I showed in my original RFC of
> > > > this feature.
> > > > 
> > > >     
> > > 
> > > Indeed.
> > > 
> > > Although I had assumed that tracepoints already had appropriate jump label magic.  
> > 
> > It does. But that's not the problem I was trying to solve. It's that
> > tracing took a 8% noise dive with retpolines when enabled (hackbench
> > slowed down by 8% with all the trace events enabled compared to all
> > trace events enabled without retpoline). That is, normal users (those
> > not tracinng) are not affected by trace events slowing down by
> > retpoline. Those that care about performance when they are tracing, are
> > affected by retpoline, quite drastically.
> > 
> > I'm doing another test run and measurements, to see how the unoptimized
> > trampolines help, followed by the trampoline case.  
> 
> Are you sure you're using unoptimized?  Optimized is the default on
> x86-64 (with my third patch).
> 

Yes, because I haven't applied that third patch yet ;-)

Then I'll apply it and see how much that improves things.

-- Steve

  reply	other threads:[~2018-11-09 19:59 UTC|newest]

Thread overview: 57+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-08 21:15 [PATCH RFC 0/3] Static calls Josh Poimboeuf
2018-11-08 21:15 ` [RFC PATCH 1/3] static_call: Add static call infrastructure Josh Poimboeuf
2018-11-09  9:51   ` Ard Biesheuvel
2018-11-09 14:55     ` Josh Poimboeuf
2018-11-09 13:39   ` Ard Biesheuvel
2018-11-09 15:10     ` Josh Poimboeuf
2018-11-09 15:14       ` Ard Biesheuvel
2018-11-09 17:25         ` Ard Biesheuvel
2018-11-09 17:31           ` Josh Poimboeuf
2018-11-09 17:33             ` Ard Biesheuvel
2018-11-09 17:46               ` Josh Poimboeuf
2018-11-09 17:52                 ` Ard Biesheuvel
2018-11-09 17:53                   ` Ard Biesheuvel
2018-11-09 19:03                     ` Josh Poimboeuf
2018-11-09 19:12                       ` Ard Biesheuvel
2018-11-09 17:33             ` Josh Poimboeuf
2018-11-09 18:33   ` Steven Rostedt
2018-11-09 19:35     ` Josh Poimboeuf
2018-11-09 19:57       ` Steven Rostedt
2018-11-09 20:34         ` Josh Poimboeuf
2018-11-10  5:10           ` Steven Rostedt
2018-11-10 11:58             ` Ard Biesheuvel
2018-11-10 13:09               ` Steven Rostedt
2018-11-12  3:07                 ` Josh Poimboeuf
2018-11-12  4:39                   ` Ard Biesheuvel
2018-11-12  4:56                     ` Josh Poimboeuf
2018-11-12  5:02                       ` Ard Biesheuvel
2018-11-10 11:56           ` Ard Biesheuvel
2018-11-08 21:15 ` [RFC PATCH 2/3] x86/static_call: Add x86 unoptimized static call implementation Josh Poimboeuf
2018-11-08 21:15 ` [RFC PATCH 3/3] x86/static_call: Add optimized static call implementation for 64-bit Josh Poimboeuf
2018-11-08 21:24 ` [PATCH RFC 0/3] Static calls Josh Poimboeuf
2018-11-09  7:28 ` Ingo Molnar
2018-11-09  7:50   ` Ingo Molnar
2018-11-09 13:50   ` Ard Biesheuvel
2018-11-09 15:20     ` Josh Poimboeuf
2018-11-10 23:20     ` Peter Zijlstra
2018-11-11 13:42       ` Ard Biesheuvel
2018-11-11 14:25         ` Peter Zijlstra
2018-11-09 14:45   ` Josh Poimboeuf
2018-11-12  5:02     ` Ingo Molnar
2018-11-12  5:30       ` Josh Poimboeuf
2018-11-12  9:39         ` Ard Biesheuvel
2018-11-12 22:52           ` Josh Poimboeuf
2018-11-12 17:03         ` Steven Rostedt
2018-11-12 22:56           ` Josh Poimboeuf
2018-11-12  5:34       ` Andy Lutomirski
2018-11-09 15:16   ` Andy Lutomirski
2018-11-09 15:21     ` Josh Poimboeuf
2018-11-09 16:41       ` Josh Poimboeuf
2018-11-09 18:42         ` Steven Rostedt
2018-11-09 19:05           ` Andy Lutomirski
2018-11-09 19:37             ` Steven Rostedt
2018-11-09 19:44               ` Josh Poimboeuf
2018-11-09 19:59                 ` Steven Rostedt [this message]
2018-11-09 20:36                   ` Josh Poimboeuf
2018-11-10 15:13             ` Masami Hiramatsu
2018-11-09 20:53     ` Rasmus Villemoes

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