Re: [Summit topic] Let's have chalk talks (part 1/?)
- From
Ævar Arnfjörð Bjarmason <avarab@gmail.com>
- Date
- Oct 25, 2021, 21:20 UTC
- Message-ID
- <211025.865ytk3imw.gmgdl@evledraar.gmail.com>
- In-Reply-To
- <b485b282-2b26-b9ab-da5d-ea59f5fcf463@iee.email>
On Mon, Oct 25 2021, Philip Oakley wrote:
Show 35 quoted lines
> On 22/10/2021 08:51, Johannes Schindelin wrote: >> Apparently I have to send this in chunks, to fool the Bayes filter of our >> beloved mailing list into doing The Right Thing. >> >> This session was led by Emily Shaffer. Supporting cast: Ævar Arnfjörð >> Bjarmason, brian m. carlson, CB Bailey, and Junio Hamano. >> >> Notes: >> >> 1. What’s a public chalk talk? >> >> 1. At Google, once a week, the team meets up with no particular topic in >> mind, or a couple topics, very informal >> >> 2. One person’s turn each week to give an informal talk with a white >> board (not using chalk) >> >> 3. Topic should be technical and of interest to the presenter > [...] > > A 'listener' perspective.. > > At the summit, the packfile's packing algorithm was mentioned as a > historic 'chalk talk' that's now in the technical documentation. > > In the meantime, while chatting to a colleague about the birthday > paradox and its relation to Bloom filters, I realised I didn't > understand what our Bloom filters were trying to do and what they recorded. > > I had a look at the code and documentation, but there isn't much there > about our Bloom filter implementation. A chalk talk could later be used > in the same manner as the packfile discussion to show what the filters do? > > If there is someone who'd like to talk through what the Bloom filters > are doing in Git then I'd be all ears.
That sounds like a good idea for a topic, not to take away from any of that discussion, but I believe the bloom filters we have are exclusively used for path filtering if they exist in the commit-graph.
I.e. for:
git rev-list -- $path
See c525ce95b46 (commit-graph: check all leading directories in changed path Bloom filters, 2020-07-01) for one use-case and benchmark numbers.