The following revision refers to this bug:
  https://chromium.googlesource.com/aosp/platform/system/update_engine/+/3d32f85211f914faca4cb3a368b49c05c7e7ff98

commit 3d32f85211f914faca4cb3a368b49c05c7e7ff98
Author: Simon Glass <sjg@chromium.org>
Date: Wed Jul 19 19:34:34 2017

update_engine: Reduce verbosity of delta_generator

This outputs ~4000 lines of the form:

  0.00%         48 REPLACE_BZ <boot-operation-2>

which is not very useful in the build. Update it to show only unique lines
with a count of how many times that line was repeated.

BUG= chromium:737687 
TEST=FEATURES=test emerge-reef update_engine
See the output. I have not added a specific test for this since it is
really just debug output IMO.
Change-Id: I15149733216ba0516c62f99e5968768ec4fa3d20
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/553579
Reviewed-by: Ben Chan <benchan@chromium.org>

[modify] https://crrev.com/3d32f85211f914faca4cb3a368b49c05c7e7ff98/payload_generator/payload_file.cc

Example of the change here:

https://uberchromegw.corp.google.com/i/chromeos/builders/reef-release/builds/1314/steps/steps/logs/stdio

[0720/050629:INFO:payload_file.cc(244)] Writing final delta file data blobs...
[0720/050629:INFO:payload_file.cc(344)]   0.00%          0 SOURCE_COPY   <identical-blocks>:0 2238
[0720/050629:INFO:payload_file.cc(344)]   0.01%         43 REPLACE_BZ    <zeros>:0 477
[0720/050629:INFO:payload_file.cc(344)]   0.01%         44 REPLACE_BZ    <zeros>:0 2
[0720/050629:INFO:payload_file.cc(344)]   0.01%         45 REPLACE_BZ    <zeros>:0 3
[0720/050629:INFO:payload_file.cc(344)]   0.01%         46 REPLACE_BZ    <zeros>:0 1053
[0720/050629:INFO:payload_file.cc(344)]   0.01%         47 REPLACE_BZ    <zeros>:0 88
[0720/050629:INFO:payload_file.cc(344)]   0.01%         48 REPLACE_BZ    <zeros>:0 33
[0720/050629:INFO:payload_file.cc(344)]   0.01%         48 REPLACE_BZ    <zeros>:0:0 1
[0720/050629:INFO:payload_file.cc(344)]   0.01%         48 REPLACE_BZ    <zeros>:1:0 1
[0720/050629:INFO:payload_file.cc(344)]   0.01%         48 REPLACE_BZ    <zeros>:2:0 1
[0720/050629:INFO:payload_file.cc(344)]   0.01%         48 REPLACE_BZ    <zeros>:3:0 1
[0720/050629:INFO:payload_file.cc(344)]   0.01%         48 REPLACE_BZ    <zeros>:4:0 1
[0720/050629:INFO:payload_file.cc(344)]   0.01%         48 REPLACE_BZ    <zeros>:5:0 1
[0720/050629:INFO:payload_file.cc(344)]   0.02%         49 REPLACE_BZ    <zeros>:0 6
[0720/050629:INFO:payload_file.cc(344)]  76.50%     245753 -             <manifest-metadata> 1
[0720/050629:INFO:payload_file.cc(354)] 100.00%     321227               <total> 1


There is still a lot of output from the earlier run as each line is unique.

That's a full payload so every operation has a unique name, and it's only a few hundreds lines, I think it's okay compared to all the other logs (the entire log is more than 200k lines, so only <0.5%).

It's about 900 lines. It is down to ~1/5 of what is was so it is better. If you find that you no-longer need the logging, then we can change it to use fine logging as per https://chromium-review.googlesource.com/c/553579/1