From: Ingo Molnar <mingo@kernel•org>
To: Linus Torvalds <torvalds@linux-foundation•org>
Cc: Kees Cook <keescook@chromium•org>,
Linux Kernel Mailing List <linux-kernel@vger•kernel.org>,
Rik van Riel <riel@redhat•com>,
Casey Schaufler <casey@schaufler-ca•com>,
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Brad Spengler <spender@grsecurity•net>,
Russell King <linux@armlinux•org.uk>,
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Benjamin Herrenschmidt <benh@kernel•crashing.org>,
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Tony Luck <tony.luck@intel•com>,
Fenghua Yu <fenghua.yu@intel•com>,
"David S. Miller" <davem@davemloft•net>,
the arch/x86 maintainers <x86@kernel•org>,
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Peter Zijlstra <a.p.zijlstra@chello•nl>
Subject: Re: [PATCH 0/9] mm: Hardened usercopy
Date: Fri, 8 Jul 2016 20:23:44 +0200 [thread overview]
Message-ID: <20160708182344.GC4429@gmail.com> (raw)
In-Reply-To: <CA+55aFzv4kQitzhWgxRAi5XXM30f70d4dbTGkr7t=fZSh4r3Ow@mail.gmail.com>
* Linus Torvalds <torvalds@linux-foundation•org> wrote:
> On Fri, Jul 8, 2016 at 1:46 AM, Ingo Molnar <mingo@kernel•org> wrote:
> >
> > Could you please try to find some syscall workload that does many small user
> > copies and thus excercises this code path aggressively?
>
> Any stat()-heavy path will hit cp_new_stat() very heavily. Think the
> usual kind of "traverse the whole tree looking for something". "git
> diff" will do it, just checking that everything is up-to-date.
>
> That said, other things tend to dominate.
So I think a cached 'find /usr >/dev/null' might be a good one as well:
triton:~/tip> strace -c find /usr >/dev/null
% time seconds usecs/call calls errors syscall
------ ----------- ----------- --------- --------- ----------------
47.09 0.006518 0 254697 newfstatat
26.20 0.003627 0 254795 getdents
14.45 0.002000 0 1147411 fcntl
7.33 0.001014 0 509811 close
3.28 0.000454 0 128220 1 openat
1.52 0.000210 0 128230 fstat
0.27 0.000016 0 12810 write
0.00 0.000000 0 10 read
triton:~/tip> perf stat --repeat 3 -e cycles:u,cycles:k,cycles find /usr >/dev/null
Performance counter stats for 'find /usr' (3 runs):
1,594,437,143 cycles:u ( +- 2.76% )
2,570,544,009 cycles:k ( +- 2.50% )
4,164,981,152 cycles ( +- 2.59% )
0.929883686 seconds time elapsed ( +- 2.57% )
... and it's dominated by kernel overhead, with a fair amount of memcpy overhead
as well:
1.22% find [kernel.kallsyms] [k] copy_user_enhanced_fast_string
But maybe there are simple shell commands that are even more user-memcpy intense?
Thanks,
Ingo
next prev parent reply other threads:[~2016-07-08 18:23 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-06 22:25 [PATCH 0/9] mm: Hardened usercopy Kees Cook
2016-07-06 22:25 ` [PATCH 1/9] " Kees Cook
2016-07-07 5:37 ` Baruch Siach
2016-07-07 17:25 ` Kees Cook
2016-07-07 18:35 ` Baruch Siach
2016-07-07 7:42 ` Thomas Gleixner
2016-07-07 17:29 ` Kees Cook
2016-07-07 19:34 ` Thomas Gleixner
2016-07-07 8:01 ` Arnd Bergmann
2016-07-07 17:37 ` Kees Cook
2016-07-08 5:34 ` Michael Ellerman
2016-07-08 9:22 ` Arnd Bergmann
2016-07-07 16:19 ` Rik van Riel
2016-07-07 16:35 ` Rik van Riel
2016-07-07 17:41 ` Kees Cook
2016-07-06 22:25 ` [PATCH 2/9] x86/uaccess: Enable hardened usercopy Kees Cook
2016-07-06 22:25 ` [PATCH 3/9] ARM: uaccess: " Kees Cook
2016-07-06 22:25 ` [PATCH 4/9] arm64/uaccess: " Kees Cook
2016-07-07 10:07 ` Mark Rutland
2016-07-07 17:19 ` Kees Cook
2016-07-06 22:25 ` [PATCH 5/9] ia64/uaccess: " Kees Cook
2016-07-06 22:25 ` [PATCH 6/9] powerpc/uaccess: " Kees Cook
2016-07-06 22:25 ` [PATCH 7/9] sparc/uaccess: " Kees Cook
2016-07-06 22:25 ` [PATCH 8/9] mm: SLAB hardened usercopy support Kees Cook
2016-07-06 22:25 ` [PATCH 9/9] mm: SLUB " Kees Cook
2016-07-07 4:35 ` Michael Ellerman
[not found] ` <577ddc18.d351190a.1fa54.ffffbe79SMTPIN_ADDED_BROKEN@mx.google.com>
2016-07-07 18:56 ` [kernel-hardening] " Kees Cook
2016-07-08 10:19 ` Michael Ellerman
2016-07-08 13:45 ` Christoph Lameter
2016-07-08 16:07 ` Kees Cook
2016-07-08 16:20 ` Christoph Lameter
2016-07-08 17:41 ` Kees Cook
2016-07-08 20:48 ` Kees Cook
2016-07-09 5:58 ` Michael Ellerman
2016-07-09 6:07 ` Michael Ellerman
[not found] ` <57809299.84b3370a.5390c.ffff9e58SMTPIN_ADDED_BROKEN@mx.google.com>
2016-07-09 6:17 ` Valdis.Kletnieks
2016-07-09 17:07 ` Kees Cook
2016-07-11 6:08 ` Joonsoo Kim
2016-07-07 7:30 ` [PATCH 0/9] mm: Hardened usercopy Christian Borntraeger
2016-07-07 17:27 ` Kees Cook
2016-07-08 8:46 ` Ingo Molnar
2016-07-08 16:19 ` Linus Torvalds
2016-07-08 18:23 ` Ingo Molnar [this message]
2016-07-09 2:22 ` Laura Abbott
2016-07-09 2:44 ` Rik van Riel
2016-07-09 7:55 ` Ingo Molnar
2016-07-09 8:25 ` Ard Biesheuvel
2016-07-09 12:58 ` Laura Abbott
2016-07-09 17:03 ` Kees Cook
2016-07-09 17:01 ` Kees Cook
2016-07-09 21:27 ` Andy Lutomirski
2016-07-09 23:16 ` PaX Team
2016-07-10 9:16 ` Ingo Molnar
2016-07-10 12:03 ` PaX Team
2016-07-10 12:38 ` Andy Lutomirski
2016-07-11 18:40 ` Kees Cook
2016-07-11 18:34 ` Kees Cook
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