Messages in this thread | | | Date | Tue, 3 May 2016 12:16:39 -0700 | Subject | Re: [PATCH v2 3/4] x86, boot: Implement ASLR for kernel memory sections (x86_64) | From | Thomas Garnier <> |
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I don't see much difference. I will update the commits on next iteration with the following:
Kernbench shows almost no difference (-+ less than 1%):
Before:
Average Optimal load -j 12 Run (std deviation): Elapsed Time 102.63 (1.2695) User Time 1034.89 (1.18115) System Time 87.056 (0.456416) Percent CPU 1092.9 (13.892) Context Switches 199805 (3455.33) Sleeps 97907.8 (900.636)
After:
Average Optimal load -j 12 Run (std deviation): Elapsed Time 102.489 (1.10636) User Time 1034.86 (1.36053) System Time 87.764 (0.49345) Percent CPU 1095 (12.7715) Context Switches 199036 (4298.1) Sleeps 97681.6 (1031.11)
Hackbench shows 0% difference on average (hackbench 90 repeated 10 times)
attemp,before,after 1,0.076,0.069 2,0.072,0.069 3,0.066,0.066 4,0.066,0.068 5,0.066,0.067 6,0.066,0.069 7,0.067,0.066 8,0.063,0.067 9,0.067,0.065 10,0.068,0.071 average,0.0677,0.0677
Thanks, Thomas
On Mon, May 2, 2016 at 3:00 PM, Dave Hansen <dave.hansen@linux.intel.com> wrote: > On 05/02/2016 02:41 PM, Thomas Garnier wrote: >> -#define __PAGE_OFFSET _AC(0xffff880000000000, UL) >> +#define __PAGE_OFFSET_BASE _AC(0xffff880000000000, UL) >> +#ifdef CONFIG_RANDOMIZE_MEMORY >> +#define __PAGE_OFFSET page_offset_base >> +#else >> +#define __PAGE_OFFSET __PAGE_OFFSET_BASE >> +#endif /* CONFIG_RANDOMIZE_MEMORY */ > > Do you have any data about the performance impact of this change? It's > not necessary to have it to merge something like this, I'm just curious > how bad it is.
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