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From: Joanne Koong <joannekoong@fb.com>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>,
	Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Martin KaFai Lau <kafai@fb.com>, bpf <bpf@vger.kernel.org>,
	Kernel Team <Kernel-team@fb.com>
Subject: Re: [PATCH v3 bpf-next 1/5] bpf: Add bloom filter map implementation
Date: Tue, 28 Sep 2021 20:38:45 -0700	[thread overview]
Message-ID: <c74f5df1-4953-29ca-2217-e63c3f112463@fb.com> (raw)
In-Reply-To: <20210929031715.wvicuaf6iixm7xsb@ast-mbp.dhcp.thefacebook.com>

On 9/28/21 8:17 PM, Alexei Starovoitov wrote:

> On Tue, Sep 28, 2021 at 05:14:55PM -0700, Andrii Nakryiko wrote:
>> So for Bloom filter you get performance advantage from a dedicated map
>> (due to having just 1 helper call to do N hashing operations). For
>> pure bitset, there seems to be little benefit at all because it is
>> basically ARRAY.
> I brought up bitset only as an idea to make bloomfilter map a bit more
> generic and was looking for feedback whether to call the new map
> "bitset that allows bloomfilter operations" or call it
> "bloomfilter that simplifies to bitset" with nr_hashes=0.
>
> It sounds that using bloomfilter as a base name fits better.
I am in favor of calling the new map "bitset that allows bloom filter 
operations"
and having the map be BPF_MAP_TYPE_BITSET everywhere.
To me that is more intuitive since the bloom filter is based on top of a 
bitset.
And I think more people will generally be using bitsets than the bloom 
filter.
Additionally, for users who don't know or care what a bloom filter is, they
might skip this map type altogether and not realize it also can be used as
a bitset.
>> I haven't found SPDX header or any mention of GPL in
>> include/linux/jhash.h, so I assumed someone can just copy paste the
>> code (given the references to public domain). Seems like that's not
>> the case? Just curious about implications, license-wise, if there is
>> no SPDX? Is it still considered GPL?
> I believe so. Every project that copy pasted jhash from the kernel
> add SPDX gpl-2 to its source.

  reply	other threads:[~2021-09-29  3:38 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-21 21:02 [PATCH v3 bpf-next 0/5] Implement bloom filter map Joanne Koong
2021-09-21 21:02 ` [PATCH v3 bpf-next 1/5] bpf: Add bloom filter map implementation Joanne Koong
2021-09-21 23:44   ` Andrii Nakryiko
2021-09-22 19:06     ` Joanne Koong
2021-09-22 19:38       ` Martin KaFai Lau
2021-09-22 20:52         ` Andrii Nakryiko
2021-09-22 22:08           ` Martin KaFai Lau
2021-09-22 23:07             ` Andrii Nakryiko
2021-09-23  1:28               ` Martin KaFai Lau
2021-09-23 18:42                 ` Andrii Nakryiko
2021-09-23 19:42                   ` Martin KaFai Lau
2021-09-23 20:30                     ` Alexei Starovoitov
2021-09-23 21:12                       ` Andrii Nakryiko
2021-09-23 22:28                         ` Joanne Koong
2021-09-23 23:46                           ` Martin KaFai Lau
2021-09-24  2:23                           ` Andrii Nakryiko
2021-09-24 16:32                             ` Joanne Koong
2021-09-24 23:12                               ` Andrii Nakryiko
2021-09-27 16:41                                 ` Alexei Starovoitov
2021-09-27 21:14                                   ` Andrii Nakryiko
2021-09-27 23:51                                     ` Alexei Starovoitov
2021-09-28  0:36                                       ` Andrii Nakryiko
2021-09-28 16:21                                         ` Alexei Starovoitov
     [not found]                                           ` <aa967ed2-a958-f995-3a09-bbd6b6e775d4@fb.com>
2021-09-28 23:54                                             ` Andrii Nakryiko
2021-09-29  1:54                                               ` Joanne Koong
2021-09-29  0:14                                           ` Andrii Nakryiko
2021-09-29  3:17                                             ` Alexei Starovoitov
2021-09-29  3:38                                               ` Joanne Koong [this message]
2021-09-28  1:09                                 ` Martin KaFai Lau
2021-09-22 20:44       ` Andrii Nakryiko
2021-09-21 21:02 ` [PATCH v3 bpf-next 2/5] libbpf: Allow the number of hashes in bloom filter maps to be configurable Joanne Koong
2021-09-21 22:24   ` Joanne Koong
2021-09-22 23:14     ` Andrii Nakryiko
2021-09-21 23:57   ` Andrii Nakryiko
2021-09-21 21:02 ` [PATCH v3 bpf-next 3/5] selftests/bpf: Add bloom filter map test cases Joanne Koong
2021-09-21 21:02 ` [PATCH v3 bpf-next 4/5] bpf/benchs: Add benchmark test for bloom filter maps Joanne Koong
2021-09-21 21:02 ` [PATCH v3 bpf-next 5/5] bpf/benchs: Add benchmarks for comparing hashmap lookups with vs. without bloom filter Joanne Koong

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