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  • Committer: John Arbash Meinel
  • Date: 2010-08-05 16:27:35 UTC
  • mto: This revision was merged to the branch mainline in revision 5374.
  • Revision ID: john@arbash-meinel.com-20100805162735-172opvx34sr5gpbl
Find a case where we are wasting a bit of memory.

Specifically the 'build_details' tuple contains a lot of wasted references,
and we hold on to one of these for each record we are fetching.
And for something like 'bzr pack', that is all keys.

For just loading all text build details on my bzr+ repository, With:
locations = b.repository.texts._index.get_build_details(b.repository.texts.keys())
This drops the memory consumption from:
WorkingSize   77604KiB
 to
WorkingSize   64640KiB

Or around 10.6MB. I worked it out to a savings of about 80 bytes/record
on data that can have hundreds of thousands of records (in 32-bit).

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Lines of Context:
bzrlib/diff-delta.c
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    free(index);
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}
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unsigned long
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sizeof_delta_index(struct delta_index *index)
 
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unsigned long sizeof_delta_index(struct delta_index *index)
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{
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    if (index)
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        return index->memsize;
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             const void *trg_buf, unsigned long trg_size,
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             unsigned long *delta_size, unsigned long max_size)
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{
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    unsigned int i, outpos, outsize, moff, val;
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    int msize;
 
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    unsigned int i, outpos, outsize, moff, msize, val;
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    const struct source_info *msource;
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    int inscnt;
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    const unsigned char *ref_data, *ref_top, *data, *top;
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                 entry++) {
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                const unsigned char *ref;
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                const unsigned char *src;
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                int ref_size;
 
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                unsigned int ref_size;
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                if (entry->val != val)
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                    continue;
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                ref = entry->ptr;
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                 * match more bytes with this location that we have already
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                 * matched.
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                 */
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                if (ref_size > (top - src))
 
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                if (ref_size > top - src)
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                    ref_size = top - src;
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                if (ref_size <= msize)
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                    break;
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                /* See how many bytes actually match at this location. */
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                while (ref_size-- && *src++ == *ref)
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                    ref++;
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                if (msize < (ref - entry->ptr)) {
 
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                if (msize < ref - entry->ptr) {
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                    /* this is our best match so far */
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                    msize = ref - entry->ptr;
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                    msource = entry->src;