From: Ingo Molnar <mingo@kernel.org>
Subject: Re: x86: PIE support and option to extend KASLR randomization
Date: Fri, 25 Aug 2017 10:04:43 +0200
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Cc: Herbert Xu <herbert@gondor.apana.org.au>,
	"David S . Miller" <davem@davemloft.net>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, "H . Peter Anvin" <hpa@zytor.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Josh Poimboeuf <jpoimboe@redhat.com>, Arnd Bergmann <arnd@arndb.de>,
	Matthias Kaehlcke <mka@chromium.org>,
	Boris Ostrovsky <boris.ostrovsky@oracle.com>,
	Juergen Gross <jgross@suse.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Radim =?utf-8?B?S3LEjW3DocWZ?= <rkrcmar@redhat.com>,
	Joerg Roedel <joro@8bytes.org>,
	Tom Lendacky <thomas.lendacky@amd.com>,
	Andy Lutomirski <luto@kernel.org>, Borislav Petkov <bp@suse.de>,
	Brian Gerst <brgerst@gmail.com>,
	"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
	"Rafael J . Wysocki" <rjw@rjwysocki.net>,
	Len Brown <len.brown@intel.com>, Pavel Machek <pavel@ucw.cz>,
	Tejun Heo <tj@kernel.org>, Christoph Lamete
To: Thomas Garnier <thgarnie@google.com>
Sender: Ingo Molnar <mingo.kernel.org@gmail.com>
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* Thomas Garnier <thgarnie@google.com> wrote:

> With the fix for function tracing, the hackbench results have an
> average of +0.8 to +1.4% (from +8% to +10% before). With a default
> configuration, the numbers are closer to 0.8%.
> 
> On the .text size, with gcc 4.9 I see +0.8% on default configuration
> and +1.180% on the ubuntu configuration.

A 1% text size increase is still significant. Could you look at the disassembly, 
where does the size increase come from?

Thanks,

	Ingo