From: Taylor Blau <email@example.com> To: Jonathan Nieder <firstname.lastname@example.org> Cc: Taylor Blau <email@example.com>, Christian Couder <firstname.lastname@example.org>, Jeff King <email@example.com>, git <firstname.lastname@example.org>, Christian Couder <email@example.com>, Johannes Schindelin <Johannes.Schindelin@gmx.de> Subject: Re: Git in Outreachy? Date: Wed, 9 Sep 2020 22:19:16 -0400 [thread overview] Message-ID: <20200910021916.GA503@nand.local> (raw) In-Reply-To: <20200910013915.GD667601@google.com> On Wed, Sep 09, 2020 at 06:39:15PM -0700, Jonathan Nieder wrote: > Taylor Blau wrote: > In other words: this isn't about changing how tests are executed --- > it's about going from patches on list to git commits that can be > tested. Fair enough; it sounds like a Snowpatch-like tool might be useful for that case. > [...] > >> - formats: on-disk reverse idx > > > > As a heads up, I think that I am going to start working on (an > > alternative to) this myself, > > Neat! I look forward to seeing what you build. (Is this related to > the bitmaps-using-midx-ordering work?) You guessed it ;-). It's sort of a tricky issue: the pack-objects code needs to know things like the position of an object in index order so that it can look at the offset of the next object and determine its size. But, in the multi-pack case, things aren't so simple. It would be nice if we could look at a bit position and say "you are at bit position N and there are M different packs before you, so I know what position you are within your pack", but this can't be done in general when you have duplicate objects among packs in your MIDX. The MIDX is only going to choose one of them, and so you don't know how many "holes" are present before you. In my development version, I have a bitmap extension I'm calling the "rev-cache" which acts like a mapping between bit position and MIDX name order (which can then be used to look up auxiliary info like which pack an object came from, its position in the pack's index order, and so on). But, having an on-disk mapping between objects and their position in different orderings will be useful not only for this, but for: - avoiding building a reverse index in memory from scratch (which can occupy quite a bit of the heap in some repositories that we see), and - dropping GitHub's custom "bit-cache" extension, which maps objects from name order to bit position. Anyway, obviously not related to Outreachy, and obviously many more details to come once I have patches that are more mature, but I couldn't help myself in the meantime. > Thanks, > Jonathan > > >> [*] https://github.com/ruscur/snowpatch Thanks, Taylor
next prev parent reply other threads:[~2020-09-10 2:21 UTC|newest] Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-08-28 6:56 Jeff King 2020-08-31 6:55 ` Christian Couder 2020-09-03 6:00 ` Jonathan Nieder 2020-09-04 14:14 ` Philip Oakley 2020-09-07 18:49 ` Johannes Schindelin 2020-09-16 15:16 ` Philip Oakley 2020-09-16 18:43 ` Johannes Schindelin 2020-09-17 14:42 ` Philip Oakley 2020-09-09 18:26 ` Taylor Blau 2020-09-10 1:39 ` Jonathan Nieder 2020-09-10 2:19 ` Taylor Blau [this message] 2020-09-16 9:12 ` Christian Couder 2020-09-16 6:42 ` Christian Couder 2020-08-31 17:41 ` Junio C Hamano 2020-08-31 18:05 ` Emily Shaffer 2020-09-01 12:51 ` Jeff King 2020-09-03 5:41 ` Jeff King 2020-09-15 17:35 ` Jeff King 2020-09-15 17:55 ` Kaartic Sivaraam 2020-09-15 18:02 ` Jeff King 2020-09-19 8:12 ` Christian Couder 2020-09-19 15:10 ` Phillip Wood 2020-09-16 8:45 ` Christian Couder 2020-09-02 4:00 ` Johannes Schindelin 2020-09-16 9:01 ` Christian Couder 2020-09-16 9:45 ` Phillip Wood 2020-09-17 9:43 ` Christian Couder 2020-09-17 10:14 ` Phillip Wood 2020-09-18 8:37 ` Christian Couder 2020-09-17 15:34 ` Elijah Newren 2020-09-18 8:42 ` Christian Couder 2020-09-27 16:59 ` Kaartic Sivaraam 2020-09-27 21:16 ` Christian Couder 2020-10-29 10:13 ` Christian Couder 2020-09-06 18:56 ` Kaartic Sivaraam 2020-09-07 18:55 ` Johannes Schindelin 2020-09-16 9:35 ` Christian Couder 2020-09-16 20:27 ` Johannes Schindelin 2020-09-19 7:40 ` Christian Couder 2020-09-20 15:06 ` Johannes Schindelin 2020-09-20 16:31 ` Kaartic Sivaraam 2020-09-21 4:22 ` Christian Couder 2020-09-21 7:59 ` Kaartic Sivaraam 2020-09-21 20:56 ` Shourya Shukla 2021-09-03 2:40 Taylor Blau 2021-09-03 18:33 ` Emily Shaffer 2021-09-04 4:30 ` Christian Couder 2021-09-04 7:40 ` ZheNing Hu 2021-09-04 12:50 ` Jeff King 2021-09-05 8:58 ` ZheNing Hu 2021-09-06 12:36 ` Matheus Tavares Bernardino 2021-09-07 5:50 ` ZheNing Hu 2021-09-04 17:51 ` Taylor Blau 2021-09-18 16:10 ` Taylor Blau 2021-09-20 7:45 ` ZheNing Hu 2021-09-20 14:52 ` Christian Couder 2021-09-20 15:15 ` Christian Couder 2021-09-21 5:41 ` ZheNing Hu 2021-09-21 15:39 ` Christian Couder 2021-09-22 15:01 ` ZheNing Hu 2021-09-21 5:39 ` ZheNing Hu 2021-09-21 15:35 ` Christian Couder 2021-09-22 14:58 ` ZheNing Hu 2021-09-21 21:25 ` Taylor Blau 2021-09-29 14:18 ` Christian Couder 2021-09-29 17:34 ` Taylor Blau 2021-09-29 20:30 ` Taylor Blau
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