Re: [PATCH 2/2] pack-objects: optimize "recency order"

On Thu, Oct 27, 2011 at 23:49, Ævar Arnfjörð Bjarmason [off-list ref] wrote:

Actually it just seems slow in general, not just on repositories with
a lot of tags, on linux-2.6.git with this patch:

Here's profiling with gprof for everything with >1% of execution time
with the patch applied:

    Each sample counts as 0.01 seconds.
      %   cumulative   self              self     total
     time   seconds   seconds    calls   s/call   s/call  name
     21.07     15.99    15.99  2184059     0.00     0.00
add_descendants_to_write_order
     20.25     31.35    15.37 1146371554     0.00     0.00  add_to_write_order
     11.94     40.41     9.06 142180385     0.00     0.00  hashcmp
      5.55     44.62     4.21 90592818     0.00     0.00  lookup_object
      4.64     48.14     3.52 72804470     0.00     0.00  hashcmp
      3.87     51.08     2.94 90007452     0.00     0.00  get_mode
      3.31     53.59     2.51 90007452     0.00     0.00  decode_tree_entry
      1.90     55.03     1.44  2184059     0.00     0.00
add_family_to_write_order
      1.79     56.39     1.36 43247856     0.00     0.00  hashcmp
      1.29     57.37     0.98                             pack_offset_sort
      1.27     58.33     0.96 90007452     0.00     0.00  update_tree_entry
      1.27     59.29     0.96 90592817     0.00     0.00  hashtable_index
      1.20     60.20     0.91  4009188     0.00     0.00  find_pack_revindex
      1.19     61.10     0.90  5899321     0.00     0.00  find_pack_entry_one
      1.12     61.95     0.85   269514     0.00     0.00
commit_list_insert_by_date
      1.08     62.77     0.82  5387773     0.00     0.00  patch_delta

And without:

    Each sample counts as 0.01 seconds.
      %   cumulative   self              self     total
     time   seconds   seconds    calls   s/call   s/call  name
     21.29      9.13     9.13 142180385     0.00     0.00  hashcmp
     10.59     13.67     4.54 90592818     0.00     0.00  lookup_object
      8.48     17.31     3.64 72638478     0.00     0.00  hashcmp
      6.60     20.14     2.83 90007452     0.00     0.00  decode_tree_entry
      6.15     22.77     2.64 90007452     0.00     0.00  get_mode
      2.99     24.05     1.28 43247182     0.00     0.00  hashcmp
      2.96     25.32     1.27 90592817     0.00     0.00  hashtable_index
      2.47     26.38     1.06 90007452     0.00     0.00  update_tree_entry
      2.26     27.35     0.97  4009188     0.00     0.00  find_pack_revindex
      2.05     28.23     0.88   269245     0.00     0.00  process_tree
      1.96     29.07     0.84   269514     0.00     0.00
commit_list_insert_by_date
      1.94     29.90     0.83                             pack_offset_sort
      1.73     30.64     0.74  5389900     0.00     0.00  patch_delta
      1.70     31.37     0.73  5885588     0.00     0.00  find_pack_entry_one
      1.38     31.96     0.59  8692967     0.00     0.00  hashcmp
      1.24     32.49     0.53  8175096     0.00     0.00
unpack_object_header_buffer
      1.14     32.98     0.49        1     0.49     0.59  write_idx_file
      1.12     33.46     0.48  5885588     0.00     0.00
nth_packed_object_offset
      1.12     33.94     0.48  6051632     0.00     0.00
locate_object_entry_hash