From: YiFei Zhu <zhuyifei1999@gmail.com>
To: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Kees Cook <keescook@chromium.org>,
YiFei Zhu <yifeifz2@illinois.edu>,
Andrea Arcangeli <aarcange@redhat.com>,
Giuseppe Scrivano <gscrivan@redhat.com>,
Will Drewry <wad@chromium.org>, bpf <bpf@vger.kernel.org>,
Jann Horn <jannh@google.com>,
Linux API <linux-api@vger.kernel.org>,
Linux Containers <containers@lists.linux-foundation.org>,
Tobin Feldman-Fitzthum <tobin@ibm.com>,
Hubertus Franke <frankeh@us.ibm.com>,
Andy Lutomirski <luto@amacapital.net>,
Valentin Rothberg <vrothber@redhat.com>,
Dimitrios Skarlatos <dskarlat@cs.cmu.edu>,
Jack Chen <jianyan2@illinois.edu>,
Josep Torrellas <torrella@illinois.edu>,
Tianyin Xu <tyxu@illinois.edu>,
kernel list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v1 0/6] seccomp: Implement constant action bitmaps
Date: Sat, 26 Sep 2020 13:11:50 -0500 [thread overview]
Message-ID: <CABqSeASMObs7HtwfM=ua9Tbx1mfHZaxCMWD6AP6-6hR4-Xcn=Q@mail.gmail.com> (raw)
In-Reply-To: <CABqSeATHtvA7qm7j_kxBsbxRCd5B=MHtxGdsYsXEJ-TRRYKTgA@mail.gmail.com>
On Fri, Sep 25, 2020 at 2:07 AM YiFei Zhu <zhuyifei1999@gmail.com> wrote:
> I'll try to profile the latter later on my qemu-kvm, with a recent
> libsecomp with binary tree and docker's profile, probably both direct
> filter attaches and filter attaches with fork(). I'm guessing if I
> have fork() the cost of fork() will overshadow seccomp() though.
I'm surprised. That is not the case as far as I can tell.
I wrote a benchmark [1] that would fork() and in the child attach a
seccomp filter, look at the CLOCK_MONOTONIC difference, then add it to
a struct timespec shared with the parent. It checks the difference
with the timespec before prctl and before fork. CLOCK_MONOTONIC
instead of CLOCK_PROCESS_CPUTIME_ID because of fork.
I ran `./seccomp_emu_bench 100000` in my qemu-kvm and here are the results:
without emulator:
Benchmarking 100000 syscalls...
19799663603 (19.8s)
seecomp attach without fork: 197996 ns
33911173847 (33.9s)
seecomp attach with fork: 339111 ns
with emulator:
Benchmarking 100000 syscalls...
54428289147 (54.4s)
seecomp attach without fork: 544282 ns
69494235408 (69.5s)
seecomp attach with fork: 694942 ns
fork seems to take around 150us, seccomp attach takes around 200us,
and the filter emulation overhead is around 350us. I had no idea that
fork was this fast. If I wrote my benchmark badly please criticise.
Given that we are doubling the time to fork() + seccomp attach filter,
I think yeah running the emulator on the first instance of a syscall,
holding a lock, is a much better idea. If I naively divide 350us by
the number of syscall + arch pairs emulated the overhead is less than
1 us and that should be okay since it only happens for the first
invocation of the particular syscall.
[1] https://gist.github.com/zhuyifei1999/d7bee62bea14187e150fef59db8e30b1
YiFei Zhu
next prev parent reply other threads:[~2020-09-26 18:12 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-23 23:29 [PATCH v1 0/6] seccomp: Implement constant action bitmaps Kees Cook
2020-09-23 23:29 ` [PATCH 1/6] seccomp: Introduce SECCOMP_PIN_ARCHITECTURE Kees Cook
2020-09-24 0:41 ` Jann Horn
2020-09-24 7:11 ` Kees Cook
2020-09-23 23:29 ` [PATCH 2/6] x86: Enable seccomp architecture tracking Kees Cook
2020-09-24 0:45 ` Jann Horn
2020-09-24 7:12 ` Kees Cook
2020-09-23 23:29 ` [PATCH 3/6] seccomp: Implement constant action bitmaps Kees Cook
2020-09-24 0:25 ` Jann Horn
2020-09-24 7:36 ` Kees Cook
2020-09-24 8:07 ` YiFei Zhu
2020-09-24 8:15 ` Kees Cook
2020-09-24 8:22 ` YiFei Zhu
2020-09-24 12:28 ` Jann Horn
2020-09-24 12:37 ` David Laight
2020-09-24 12:56 ` Jann Horn
[not found] ` <DM6PR11MB271492D0565E91475D949F5DEF390@DM6PR11MB2714.namprd11.prod.outlook.com>
2020-09-24 0:36 ` YiFei Zhu
2020-09-24 7:38 ` Kees Cook
2020-09-24 7:51 ` YiFei Zhu
2020-09-23 23:29 ` [PATCH 4/6] seccomp: Emulate basic filters for constant action results Kees Cook
2020-09-23 23:47 ` Jann Horn
2020-09-24 7:46 ` Kees Cook
2020-09-24 15:28 ` Paul Moore
2020-09-24 19:52 ` Kees Cook
2020-09-24 20:46 ` Paul Moore
2020-09-24 21:35 ` Kees Cook
2020-09-23 23:29 ` [PATCH 5/6] selftests/seccomp: Compare bitmap vs filter overhead Kees Cook
2020-09-23 23:29 ` [PATCH 6/6] [DEBUG] seccomp: Report bitmap coverage ranges Kees Cook
2020-09-24 13:40 ` [PATCH v1 0/6] seccomp: Implement constant action bitmaps Rasmus Villemoes
2020-09-24 13:58 ` YiFei Zhu
2020-09-25 5:56 ` Rasmus Villemoes
2020-09-25 7:07 ` YiFei Zhu
2020-09-26 18:11 ` YiFei Zhu [this message]
2020-09-28 20:04 ` Kees Cook
2020-09-28 20:16 ` YiFei Zhu
2020-09-24 14:05 ` Jann Horn
2020-09-24 18:57 ` Andrea Arcangeli
2020-09-24 19:18 ` Jann Horn
[not found] ` <9dbe8e3bbdad43a1872202ff38c34ca2@DM5PR11MB1692.namprd11.prod.outlook.com>
2020-09-24 19:48 ` Tianyin Xu
2020-09-24 20:00 ` Kees Cook
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