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Date: Thu, 9 Jan 2014 15:31:43 -0800
From: "Noonan, Steven" <snoonan@amazon.com>
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Subject: Re: [Qemu-devel] [PATCH 1/3] configure: add option to disable
 -fstack-protector flags
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To: Brad Smith <brad@comstyle.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>, Steven Noonan <steven@uplinklabs.net>, qemu-devel@nongnu.org, Anthony Liguori <aliguori@amazon.com>

On Thu, Jan 09, 2014 at 06:18:07PM -0500, Brad Smith wrote:
> On 09/01/14 5:40 PM, Paolo Bonzini wrote:
> >Il 09/01/2014 22:55, Steven Noonan ha scritto:
> >>From: Steven Noonan <snoonan@amazon.com>
> >>
> >>The -fstack-protector flag family is useful for ensuring safety and for
> >>debugging, but has a performance impact. Here's a boot time comparison between
> >>a QEMU build of qemu-system-arm with and without the -fstack-protector-all
> >>flag:
> >>
> >>     # WITHOUT -fstack-protector-all
> >>     [root@localhost ~]# systemd-analyze
> >>     Startup finished in 1.744s (kernel) + 11.345s (initrd) + 47.164s (userspace) = 1min 255ms
> >>
> >>     # WITH -fstack-protector-all
> >>     [root@localhost ~]# systemd-analyze
> >>     Startup finished in 1.843s (kernel) + 12.262s (initrd) + 1min 3.480s (userspace) = 1min 17.587s
> >
> >Can you try -fstack-protector-strong?
> >
> >Probably the right thing to do is to pick in order
> >-fstack-protector-strong, -fstack-protector, and nothing.
> 
> +1
> 

I think there should still be an option to turn it off, but I agree that
there are probably better flags than -fstack-protector-all. I'll try
those out and post an update here probably later this evening.