Re: [Qemu-devel] [PATCH 1/3] configure: add option to disable -fstack-protector flags

[Noonan, Steven]

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 <address@hidden>
> >>
> >>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
> >>     address@hidden ~]# systemd-analyze
> >>     Startup finished in 1.744s (kernel) + 11.345s (initrd) + 47.164s 
> >> (userspace) = 1min 255ms
> >>
> >>     # WITH -fstack-protector-all
> >>     address@hidden ~]# 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.