Hello Adar Dembo,
I'd like you to do a code review. Please visit
http://gerrit.cloudera.org:8080/9752
to review the following change.
Change subject: KUDU-972. Cache should track the memory overhead
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KUDU-972. Cache should track the memory overhead
This changes the cache 'charge' mechanism to use malloc_usable_size on
its actual allocations rather than tracking only the cached _values_.
This addresses two sources of inaccuracy:
1) we weren't counting the cache key and LRUHandle overhead, which is
apparently 104 bytes per object.
2) we weren't accounting for tcmalloc internal fragmentation, which can
be significant for allocations in our typical block size range. For
example, a 4097-byte allocation will use 4608 bytes (12% overhead). In
an insert-heavy workload most of hte cache is used for bloom blocks
which are ~4kb, so the above is a very common case.
Change-Id: I6cc69004dccb1cc372fdedbac321154e46a92263
---
M src/kudu/cfile/block_cache-test.cc
M src/kudu/cfile/block_cache.cc
M src/kudu/cfile/block_cache.h
M src/kudu/util/cache.cc
M src/kudu/util/cache.h
M src/kudu/util/nvm_cache.cc
6 files changed, 61 insertions(+), 15 deletions(-)
git pull ssh://gerrit.cloudera.org:29418/kudu refs/changes/52/9752/1
--
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Gerrit-Project: kudu
Gerrit-Branch: master
Gerrit-MessageType: newchange
Gerrit-Change-Id: I6cc69004dccb1cc372fdedbac321154e46a92263
Gerrit-Change-Number: 9752
Gerrit-PatchSet: 1
Gerrit-Owner: Todd Lipcon <[email protected]>
Gerrit-Reviewer: Adar Dembo <[email protected]>
