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From: Jiong Wang <jiong.wang@netronome.com>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>,
	Daniel Borkmann <daniel@iogearbox.net>, bpf <bpf@vger.kernel.org>,
	Network Development <netdev@vger.kernel.org>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Jiong Wang <jiong.wang@netronome.com>,
	Jakub Kicinski <jakub.kicinski@netronome.com>
Subject: Re: [PATCH] bpf: optimize constant blinding
Date: Wed, 12 Jun 2019 16:04:56 +0100	[thread overview]
Message-ID: <87sgse26av.fsf@netronome.com> (raw)
In-Reply-To: <CAADnVQLp+N8pYTgmgEGfoubqKrWrnuTBJ9z2qc1rB6+04WfgHA@mail.gmail.com>


Alexei Starovoitov writes:

> On Wed, Jun 12, 2019 at 4:32 AM Naveen N. Rao
> <naveen.n.rao@linux.vnet.ibm.com> wrote:
>>
>> Currently, for constant blinding, we re-allocate the bpf program to
>> account for its new size and adjust all branches to accommodate the
>> same, for each BPF instruction that needs constant blinding. This is
>> inefficient and can lead to soft lockup with sufficiently large
>> programs, such as the new verifier scalability test (ld_dw: xor
>> semi-random 64 bit imms, test 5 -- with net.core.bpf_jit_harden=2)
>
> Slowdown you see is due to patch_insn right?
> In such case I prefer to fix the scaling issue of patch_insn instead.
> This specific fix for blinding only is not addressing the core of the problem.
> Jiong,
> how is the progress on fixing patch_insn?

I actually was about to reply this email as we have discussed exactly the
same issue on jit blinding here:

  https://www.spinics.net/lists/bpf/msg01836.html

And sorry for the slow progress on fixing patch_insn, please give me one
more week, I will try to send out a RFC for it.

Regards,
Jiong

  reply	other threads:[~2019-06-12 15:05 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-12 11:32 [PATCH] bpf: optimize constant blinding Naveen N. Rao
2019-06-12 14:47 ` Alexei Starovoitov
2019-06-12 15:04   ` Jiong Wang [this message]
2019-06-12 15:25     ` Jiong Wang
2019-06-12 15:28       ` Alexei Starovoitov
2019-06-14 15:13         ` Jiong Wang
2019-06-14 17:05           ` Alexei Starovoitov
2019-06-14 22:28             ` Andrii Nakryiko
2019-06-17 19:47           ` Edward Cree
2019-06-17 19:59             ` Jiong Wang
2019-06-17 20:11               ` Edward Cree
2019-06-17 20:40                 ` Jiong Wang
2019-06-17 20:53                   ` Alexei Starovoitov
2019-06-17 21:01                     ` Jiong Wang
2019-06-17 21:16                   ` Edward Cree
2019-06-19 20:45                     ` Jiong Wang
2019-06-14  4:30 ` kbuild test robot

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