Messages in this thread | | | From | "Reshetova, Elena" <> | Subject | RE: [PATCH] x86/entry/64: randomize kernel stack offset upon syscall | Date | Wed, 8 May 2019 13:22:01 +0000 |
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> * Reshetova, Elena <elena.reshetova@intel.com> wrote: > > > CONFIG_PAGE_TABLE_ISOLATION=n: > > > > base: Simple syscall: 0.0510 microseconds > > get_random_bytes(4096 bytes buffer): Simple syscall: 0.0597 microseconds > > > > So, pure speed wise get_random_bytes() with 1 page per-cpu buffer wins. > > It still adds +17% overhead to the system call path, which is sad. > Why is it so expensive?
I guess I can experiment further with buffer size increase and/or using HW acceleration (I mostly played around different rdrand paths now).
What would be acceptable overheard approximately (so that I know how much I need to squeeze this thing)?
Best Regards, Elena.
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