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From: Daniel Borkmann <dborkman@redhat.com>
To: David Miller <davem@davemloft.net>
Cc: matt@ozlabs.org, kda@linux-powerpc.org, linuxppc-dev@ozlabs.org,
	netdev@vger.kernel.org, alexei.starovoitov@gmail.com
Subject: Re: [PATCH v2] PPC: bpf_jit_comp: add SKF_AD_PKTTYPE instruction
Date: Sat, 01 Nov 2014 19:31:37 +0100	[thread overview]
Message-ID: <54552709.7000409@redhat.com> (raw)
In-Reply-To: <20141101.140035.13626854970331774.davem@davemloft.net>

On 11/01/2014 07:00 PM, David Miller wrote:
> From: Denis Kirjanov <kda@linux-powerpc.org>
> Date: Sat, 1 Nov 2014 21:49:27 +0400
>
>> David, you need a feedback from other guys to apply this patch, right?
>>
>> Alexei wanted some output before/after the patch.
>> Michael Ellerman wanted the explanation what a BPF_ANC | SKF_AD_PKTTYPE means.

The BPF_ANC | SKF_AD_PKTTYPE case means that this is an ancillary
operation aka BPF extension which loads the value of skb->pkt_type
into the accumulator.

A similar transformation, that is, from BPF into eBPF insns can be
found in convert_bpf_extensions() in the SKF_AD_PKTTYPE case, or
commit 709f6c58d4dc ("sparc: bpf_jit: add SKF_AD_PKTTYPE support
to JIT") that recently enabled the same in sparc.

>> So I'm waiting  the ack/nack from them...
>
> I don't really think performance metrics are necessary just for adding
> SKF_AD_PKTTYPE support, that's sort of an over the top requirement
> if you ask me.

Right, lib/test_bpf.c actually brings the quoted output w/ numbers
for free. I think the important point was that the 'After:' case
with ``echo 1 > /proc/sys/net/core/bpf_jit_enable'' runs through for
that test case, which has been shown here.

> It's pretty obvious that we should support as many operations as
> possible to each JIT, because all of program has to do is use that
> unsupported opcode and then we have none of that program being JIT'd.

  reply	other threads:[~2014-11-01 18:31 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-10-30  6:12 [PATCH v2] PPC: bpf_jit_comp: add SKF_AD_PKTTYPE instruction Denis Kirjanov
2014-10-30 20:32 ` Alexei Starovoitov
2014-10-31  6:09   ` Denis Kirjanov
2014-11-01 16:19     ` Denis Kirjanov
2014-11-01 17:39       ` David Miller
2014-11-01 17:49         ` Denis Kirjanov
2014-11-01 18:00           ` David Miller
2014-11-01 18:31             ` Daniel Borkmann [this message]
2014-11-01 18:40     ` Daniel Borkmann
2014-11-03 17:06 ` David Miller
2014-11-03 17:21   ` Alexei Starovoitov
2014-11-03 20:29     ` David Miller
2014-11-03 23:43     ` Michael Ellerman

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