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From: Garima Singh <garimasigit@gmail.com>
To: Jakub Narebski <jnareb@gmail.com>,
	Garima Singh via GitGitGadget <gitgitgadget@gmail.com>
Cc: git@vger.kernel.org, "Derrick Stolee" <stolee@gmail.com>,
	"SZEDER Gábor" <szeder.dev@gmail.com>,
	"Jonathan Tan" <jonathantanmy@google.com>,
	"Jeff Hostetler" <jeffhost@microsoft.com>,
	"Taylor Blau" <me@ttaylorr.com>, "Jeff King" <peff@peff.net>,
	"Christian Couder" <christian.couder@gmail.com>,
	"Emily Shaffer" <emilyshaffer@gmail.com>,
	"Junio C Hamano" <gitster@pobox.com>,
	"Garima Singh" <garima.singh@microsoft.com>
Subject: Re: [PATCH v2 08/11] commit-graph: reuse existing Bloom filters during write.
Date: Mon, 24 Feb 2020 16:45:00 -0500	[thread overview]
Message-ID: <2ca9f6ab-41c4-37d2-7681-8f973204d6a2@gmail.com> (raw)
In-Reply-To: <86r1ypf62y.fsf@gmail.com>



On 2/20/2020 1:48 PM, Jakub Narebski wrote:
> "Garima Singh via GitGitGadget" <gitgitgadget@gmail.com> writes:
> 
>> From: Garima Singh <garima.singh@microsoft.com>
>>
>> Read previously computed Bloom filters from the commit-graph file if
>> possible to avoid recomputing during commit-graph write.
> 
> All right, what is written makes sense for this point in patch series.
> 
> But it my opinion it is more important to state that this commit adds
> "parsing" of the Bloom filter data from commit-graph file.  This means
> that it needs to be calculated only once, then stored in commit-graph,
> ready to be re-used.
> 

Good point. Incorporated in v3.

>>
>> See Documentation/technical/commit-graph-format for the format in which
>> the Bloom filter information is written to the commit graph file.
>>
>> To read Bloom filter for a given commit with lexicographic position
>> 'i' we need to:
>> 1. Read BIDX[i] which essentially gives us the starting index in BDAT for
>>    filter of commit i+1. It is essentially the index past the end
>>    of the filter of commit i. It is called end_index in the code.
>>
>> 2. For i>0, read BIDX[i-1] which will give us the starting index in BDAT
>>    for filter of commit i. It is called the start_index in the code.
>>    For the first commit, where i = 0, Bloom filter data starts at the
>>    beginning, just past the header in the BDAT chunk. Hence, start_index
>>    will be 0.
>>
>> 3. The length of the filter will be end_index - start_index, because
>>    BIDX[i] gives the cumulative 8-byte words including the ith
>>    commit's filter.
>>
>> We toggle whether Bloom filters should be recomputed based on the
>> compute_if_null flag.
> 
> Nitpick: the flag (the parameter) is called compute_if_not_present, not
> compute_if_null.
> 
Oops. Fixed in v3. 

>> +
>> +	end_index = get_be32(g->chunk_bloom_indexes + 4 * lex_pos);
>> +
>> +	if (lex_pos)
> 
> Wouldn't it be better to be more explicit, and write
> 
>   +	if (lex_pos > 0)
> 
> 

Sure. 

>> +		start_index = get_be32(g->chunk_bloom_indexes + 4 * (lex_pos - 1));
>> +	else
>> +		start_index = 0;
> 
> All right, here we find start_index and end_index.
> 
> It might be good idea to at least assert() that start_index <= end_index,
> though that should not happen (that is why I propose for this check to
> be compiled on only for debug builds).
> 

I will look into this. Thanks! 


>> @@ -1304,7 +1304,7 @@ static void compute_bloom_filters(struct write_commit_graph_context *ctx)
>>  
>>  	for (i = 0; i < ctx->commits.nr; i++) {
>>  		struct commit *c = sorted_by_pos[i];
>> -		struct bloom_filter *filter = get_bloom_filter(ctx->r, c);
>> +		struct bloom_filter *filter = get_bloom_filter(ctx->r, c, 1);
>>  		ctx->total_bloom_filter_data_size += sizeof(uint64_t) * filter->len;
>>  		display_progress(progress, i + 1);
>>  	}
>> @@ -2314,6 +2314,7 @@ void free_commit_graph(struct commit_graph *g)
>>  		g->data = NULL;
>>  		close(g->graph_fd);
>>  	}
>> +	free(g->bloom_filter_settings);
>>  	free(g->filename);
>>  	free(g);
> 
> Shouldn't this fixup be added to earlier commit?
> 

Yes. 

>>  }
>> diff --git a/t/helper/test-bloom.c b/t/helper/test-bloom.c
>> index 331957011b..9b4be97f75 100644
>> --- a/t/helper/test-bloom.c
>> +++ b/t/helper/test-bloom.c
>> @@ -47,7 +47,7 @@ static void get_bloom_filter_for_commit(const struct object_id *commit_oid)
>>  	struct bloom_filter *filter;
>>  	setup_git_directory();
>>  	c = lookup_commit(the_repository, commit_oid);
>> -	filter = get_bloom_filter(the_repository, c);
>> +	filter = get_bloom_filter(the_repository, c, 1);
>>  	print_bloom_filter(filter);
>>  }
> 
> I would like to see some tests, but that needs to wait for patch that
> adds --changed-paths option to the 'write' subcommand.
> 
> Things to be tested:
> 1. That after reading commit-graph with Bloom filter:
>    - that commit(s) in commit-graph have Bloom filter
>    - that commits outside commit-graph do not have Bloom filter
> 2. That incremental commit-graph feature works:
>    - for commits in deeper layer that have Bloom filter chunks
>    - for commits in deeper layer that do not have Bloom filter chunks
> 

Included in later commits. 

> Best,
> 

  reply	other threads:[~2020-02-24 21:45 UTC|newest]

Thread overview: 159+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-20 22:05 [PATCH 0/9] [RFC] Changed Paths Bloom Filters Garima Singh via GitGitGadget
2019-12-20 22:05 ` [PATCH 1/9] commit-graph: add --changed-paths option to write Garima Singh via GitGitGadget
2020-01-01 20:20   ` Jakub Narebski
2019-12-20 22:05 ` [PATCH 2/9] commit-graph: write changed paths bloom filters Garima Singh via GitGitGadget
2019-12-21 16:48   ` Philip Oakley
2020-01-06 18:44   ` Jakub Narebski
2020-01-13 19:48     ` Garima Singh
2019-12-20 22:05 ` [PATCH 3/9] commit-graph: use MAX_NUM_CHUNKS Garima Singh via GitGitGadget
2020-01-07 12:19   ` Jakub Narebski
2019-12-20 22:05 ` [PATCH 4/9] commit-graph: document bloom filter format Garima Singh via GitGitGadget
2020-01-07 14:46   ` Jakub Narebski
2019-12-20 22:05 ` [PATCH 5/9] commit-graph: write changed path bloom filters to commit-graph file Garima Singh via GitGitGadget
2020-01-07 16:01   ` Jakub Narebski
2020-01-14 15:14     ` Garima Singh
2019-12-20 22:05 ` [PATCH 6/9] commit-graph: test commit-graph write --changed-paths Garima Singh via GitGitGadget
2020-01-08  0:32   ` Jakub Narebski
2019-12-20 22:05 ` [PATCH 7/9] commit-graph: reuse existing bloom filters during write Garima Singh via GitGitGadget
2020-01-09 19:12   ` Jakub Narebski
2019-12-20 22:05 ` [PATCH 8/9] revision.c: use bloom filters to speed up path based revision walks Garima Singh via GitGitGadget
2020-01-11  0:27   ` Jakub Narebski
2020-01-15  0:08     ` Garima Singh
2019-12-20 22:05 ` [PATCH 9/9] commit-graph: add GIT_TEST_COMMIT_GRAPH_BLOOM_FILTERS test flag Garima Singh via GitGitGadget
2020-01-11 19:56   ` Jakub Narebski
2020-01-15  0:55     ` Garima Singh
2019-12-20 22:14 ` [PATCH 0/9] [RFC] Changed Paths Bloom Filters Junio C Hamano
2019-12-22  9:26 ` Christian Couder
2019-12-22  9:38   ` Jeff King
2020-01-01 12:04     ` Jakub Narebski
2019-12-22  9:30 ` Jeff King
2019-12-22  9:32   ` [PATCH 1/3] commit-graph: examine changed-path objects in pack order Jeff King
2019-12-27 14:51     ` Derrick Stolee
2019-12-29  6:12       ` Jeff King
2019-12-29  6:28         ` Jeff King
2019-12-30 14:37         ` Derrick Stolee
2019-12-30 14:51           ` Derrick Stolee
2019-12-22  9:32   ` [PATCH 2/3] commit-graph: free large diffs, too Jeff King
2019-12-27 14:52     ` Derrick Stolee
2019-12-22  9:32   ` [PATCH 3/3] commit-graph: stop using full rev_info for diffs Jeff King
2019-12-27 14:53     ` Derrick Stolee
2019-12-26 14:21   ` [PATCH 0/9] [RFC] Changed Paths Bloom Filters Derrick Stolee
2019-12-29  6:03     ` Jeff King
2019-12-27 16:11   ` Derrick Stolee
2019-12-29  6:24     ` Jeff King
2019-12-30 16:04       ` Derrick Stolee
2019-12-30 17:02       ` Junio C Hamano
2019-12-31 16:45 ` Jakub Narebski
2020-01-13 16:54   ` Garima Singh
2020-01-20 13:48     ` Jakub Narebski
2020-01-21 16:14       ` Garima Singh
2020-02-02 18:43         ` Jakub Narebski
2020-01-21 23:40 ` Emily Shaffer
2020-01-27 18:24   ` Garima Singh
2020-02-01 23:32   ` Jakub Narebski
2020-02-05 22:56 ` [PATCH v2 00/11] " Garima Singh via GitGitGadget
2020-02-05 22:56   ` [PATCH v2 01/11] commit-graph: use MAX_NUM_CHUNKS Garima Singh via GitGitGadget
2020-02-09 12:39     ` Jakub Narebski
2020-02-05 22:56   ` [PATCH v2 02/11] bloom: core Bloom filter implementation for changed paths Garima Singh via GitGitGadget
2020-02-15 17:17     ` Jakub Narebski
2020-02-16 16:49     ` Jakub Narebski
2020-02-22  0:32       ` Garima Singh
2020-02-23 13:38         ` Jakub Narebski
2020-02-24 17:34           ` Garima Singh
2020-02-24 18:20             ` Jakub Narebski
2020-02-05 22:56   ` [PATCH v2 03/11] diff: halt tree-diff early after max_changes Derrick Stolee via GitGitGadget
2020-02-17  0:00     ` Jakub Narebski
2020-02-22  0:37       ` Garima Singh
2020-02-05 22:56   ` [PATCH v2 04/11] commit-graph: compute Bloom filters for changed paths Garima Singh via GitGitGadget
2020-02-17 21:56     ` Jakub Narebski
2020-02-22  0:55       ` Garima Singh
2020-02-23 17:34         ` Jakub Narebski
2020-02-05 22:56   ` [PATCH v2 05/11] commit-graph: examine changed-path objects in pack order Jeff King via GitGitGadget
2020-02-18 17:59     ` Jakub Narebski
2020-02-24 18:29       ` Garima Singh
2020-02-05 22:56   ` [PATCH v2 06/11] commit-graph: examine commits by generation number Derrick Stolee via GitGitGadget
2020-02-19  0:32     ` Jakub Narebski
2020-02-24 20:45       ` Garima Singh
2020-02-05 22:56   ` [PATCH v2 07/11] commit-graph: write Bloom filters to commit graph file Garima Singh via GitGitGadget
2020-02-19 15:13     ` Jakub Narebski
2020-02-24 21:14       ` Garima Singh
2020-02-25 11:40         ` Jakub Narebski
2020-02-25 15:58           ` Garima Singh
2020-02-05 22:56   ` [PATCH v2 08/11] commit-graph: reuse existing Bloom filters during write Garima Singh via GitGitGadget
2020-02-20 18:48     ` Jakub Narebski
2020-02-24 21:45       ` Garima Singh [this message]
2020-02-05 22:56   ` [PATCH v2 09/11] commit-graph: add --changed-paths option to write subcommand Garima Singh via GitGitGadget
2020-02-20 20:28     ` Jakub Narebski
2020-02-24 21:51       ` Garima Singh
2020-02-25 12:10         ` Jakub Narebski
2020-02-20 22:10     ` Bryan Turner
2020-02-22  1:44       ` Garima Singh
2020-02-05 22:56   ` [PATCH v2 10/11] revision.c: use Bloom filters to speed up path based revision walks Garima Singh via GitGitGadget
2020-02-21 17:31     ` Jakub Narebski
2020-02-21 22:45     ` Jakub Narebski
2020-02-05 22:56   ` [PATCH v2 11/11] commit-graph: add GIT_TEST_COMMIT_GRAPH_CHANGED_PATHS test flag Garima Singh via GitGitGadget
2020-02-22  0:11     ` Jakub Narebski
2020-02-07 13:52   ` [PATCH v2 00/11] Changed Paths Bloom Filters SZEDER Gábor
2020-02-07 15:09     ` Garima Singh
2020-02-07 15:36       ` Derrick Stolee
2020-02-07 16:15         ` SZEDER Gábor
2020-02-07 16:33           ` Derrick Stolee
2020-02-11 19:08       ` Garima Singh
2020-02-08 23:04   ` Jakub Narebski
2020-02-21 17:41     ` Garima Singh
2020-03-29 18:36       ` Junio C Hamano
2020-03-30  0:31   ` [PATCH v3 00/16] " Garima Singh via GitGitGadget
2020-03-30  0:31     ` [PATCH v3 01/16] commit-graph: define and use MAX_NUM_CHUNKS Garima Singh via GitGitGadget
2020-03-30  0:31     ` [PATCH v3 02/16] bloom.c: add the murmur3 hash implementation Garima Singh via GitGitGadget
2020-03-30  0:31     ` [PATCH v3 03/16] bloom.c: introduce core Bloom filter constructs Garima Singh via GitGitGadget
2020-03-30  0:31     ` [PATCH v3 04/16] bloom.c: core Bloom filter implementation for changed paths Garima Singh via GitGitGadget
2020-03-30  0:31     ` [PATCH v3 05/16] diff: halt tree-diff early after max_changes Derrick Stolee via GitGitGadget
2020-03-30  0:31     ` [PATCH v3 06/16] commit-graph: compute Bloom filters for changed paths Garima Singh via GitGitGadget
2020-03-30  0:31     ` [PATCH v3 07/16] commit-graph: examine changed-path objects in pack order Jeff King via GitGitGadget
2020-03-30  0:31     ` [PATCH v3 08/16] commit-graph: examine commits by generation number Garima Singh via GitGitGadget
2020-03-30  0:31     ` [PATCH v3 09/16] diff: skip batch object download when possible Garima Singh via GitGitGadget
2020-03-30  0:31     ` [PATCH v3 10/16] commit-graph: write Bloom filters to commit graph file Garima Singh via GitGitGadget
2020-03-30  0:31     ` [PATCH v3 11/16] commit-graph: reuse existing Bloom filters during write Garima Singh via GitGitGadget
2020-03-30  0:31     ` [PATCH v3 12/16] commit-graph: add --changed-paths option to write subcommand Garima Singh via GitGitGadget
2020-03-30  0:31     ` [PATCH v3 13/16] revision.c: use Bloom filters to speed up path based revision walks Garima Singh via GitGitGadget
2020-03-30  0:31     ` [PATCH v3 14/16] revision.c: add trace2 stats around Bloom filter usage Garima Singh via GitGitGadget
2020-03-30  0:31     ` [PATCH v3 15/16] t4216: add end to end tests for git log with Bloom filters Garima Singh via GitGitGadget
2020-03-30  0:31     ` [PATCH v3 16/16] commit-graph: add GIT_TEST_COMMIT_GRAPH_CHANGED_PATHS test flag Garima Singh via GitGitGadget
2020-04-06 16:59     ` [PATCH v4 00/15] Changed Paths Bloom Filters Garima Singh via GitGitGadget
2020-04-06 16:59       ` [PATCH v4 01/15] commit-graph: define and use MAX_NUM_CHUNKS Garima Singh via GitGitGadget
2020-04-06 16:59       ` [PATCH v4 02/15] bloom.c: add the murmur3 hash implementation Garima Singh via GitGitGadget
2020-04-06 16:59       ` [PATCH v4 03/15] bloom.c: introduce core Bloom filter constructs Garima Singh via GitGitGadget
2020-04-06 16:59       ` [PATCH v4 04/15] bloom.c: core Bloom filter implementation for changed paths Garima Singh via GitGitGadget
2020-06-27 15:53         ` SZEDER Gábor
2020-04-06 16:59       ` [PATCH v4 05/15] diff: halt tree-diff early after max_changes Derrick Stolee via GitGitGadget
2020-08-04 14:47         ` SZEDER Gábor
2020-08-04 16:25           ` Derrick Stolee
2020-08-04 17:00             ` SZEDER Gábor
2020-08-04 17:31               ` Derrick Stolee
2020-08-05 17:08                 ` Derrick Stolee
2020-04-06 16:59       ` [PATCH v4 06/15] commit-graph: compute Bloom filters for changed paths Garima Singh via GitGitGadget
2020-04-06 16:59       ` [PATCH v4 07/15] commit-graph: examine changed-path objects in pack order Jeff King via GitGitGadget
2020-04-06 16:59       ` [PATCH v4 08/15] commit-graph: examine commits by generation number Garima Singh via GitGitGadget
2020-04-06 16:59       ` [PATCH v4 09/15] commit-graph: write Bloom filters to commit graph file Garima Singh via GitGitGadget
2020-05-29  8:57         ` SZEDER Gábor
2020-05-29 13:35           ` Derrick Stolee
2020-05-31 17:23             ` SZEDER Gábor
2020-07-09 17:00         ` [PATCH] commit-graph: fix "Writing out commit graph" progress counter SZEDER Gábor
2020-07-09 18:01           ` Derrick Stolee
2020-07-09 18:20             ` Derrick Stolee
2020-04-06 16:59       ` [PATCH v4 10/15] commit-graph: reuse existing Bloom filters during write Garima Singh via GitGitGadget
2020-06-19 14:02         ` SZEDER Gábor
2020-06-19 19:28           ` Junio C Hamano
2020-07-27 21:33         ` SZEDER Gábor
2020-04-06 16:59       ` [PATCH v4 11/15] commit-graph: add --changed-paths option to write subcommand Garima Singh via GitGitGadget
2020-06-07 22:21         ` SZEDER Gábor
2020-04-06 16:59       ` [PATCH v4 12/15] revision.c: use Bloom filters to speed up path based revision walks Garima Singh via GitGitGadget
2020-06-26  6:34         ` SZEDER Gábor
2020-04-06 16:59       ` [PATCH v4 13/15] revision.c: add trace2 stats around Bloom filter usage Garima Singh via GitGitGadget
2020-04-06 16:59       ` [PATCH v4 14/15] t4216: add end to end tests for git log with Bloom filters Garima Singh via GitGitGadget
2020-04-06 16:59       ` [PATCH v4 15/15] commit-graph: add GIT_TEST_COMMIT_GRAPH_CHANGED_PATHS test flag Garima Singh via GitGitGadget
2020-04-08 15:51       ` [PATCH v4 00/15] Changed Paths Bloom Filters Derrick Stolee
2020-04-08 19:21         ` Junio C Hamano
2020-04-08 20:05         ` Jakub Narębski
2020-04-12 20:34         ` Taylor Blau
2020-03-05 19:49 ` [PATCH 0/9] [RFC] " Garima Singh

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