From: Steven Rostedt <rostedt@goodmis.org>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>,
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 14:37:03 -0500 [thread overview]
Message-ID: <20181109143703.5f2205bf@gandalf.local.home> (raw)
In-Reply-To: <979DB163-EFBD-41BB-8481-155AAF526E72@amacapital.net>
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.
-- Steve
next prev parent reply other threads:[~2018-11-09 19:37 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 [this message]
2018-11-09 19:44 ` Josh Poimboeuf
2018-11-09 19:59 ` Steven Rostedt
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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