Hello Marcel Kornacker,
I'd like you to reexamine a change. Please visit
http://gerrit.cloudera.org:8080/7082
to look at the new patch set (#2).
Change subject: IMPALA-5357: Fix unixtime to UTC TimestampValue perf
......................................................................
IMPALA-5357: Fix unixtime to UTC TimestampValue perf
Fixes the severe perf issue when calling gmtime_r to convert
a unix time because that libc function takes a global lock.
Instead, use boost ptime::from_time_t when possible.
Unfortunately only a range of input times are supported
without overflowing the underlying time_duration struct
(dates between 1677-2262), so those dates outside that range
are handled with the slow path calling into gmtime_r.
This requires using a patched build of boost which
includes an upstream fix for the time_duration class, see:
https://github.com/cloudera/native-toolchain/commit/6e726b4b8164d53814f75b78a681fcf6df4a887a
Testing:
* Ran an exhaustive test run successfully.
* Wrote a test program to validate that all time_t values
between 1677 and 2262 are converted to the same ptime
when using the new code path and the old path. Doing so
required running all night, so I'm not going to attempt to
add this test. I think a single validation is acceptable.
Perf impact:
Microbenchmark of the new path (conversion using boost) and
the old path (conversion using libc gmtime_r) resulted in
the expected speedup from not using a global lock.
Machine Info: Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz
Function 10%ile 50%ile 90%ile 10%ile 50%ile 90%ile
iters/ms iters/ms iters/ms (relative) (relative) (relative)
---------------------------------------------------------------------
libc-1 0.192 0.196 0.2 1X 1X 1X
boost-1 0.333 0.34 0.34 1.73X 1.73X 1.7X
libc-2 0.112 0.115 0.116 0.584X 0.586X 0.581X
boost-2 0.627 0.654 0.667 3.26X 3.33X 3.33X
libc-4 0.042 0.0478 0.0515 0.218X 0.244X 0.258X
boost-4 0.863 1.27 1.3 4.49X 6.5X 6.5X
libc-8 0.0326 0.0328 0.0329 0.169X 0.167X 0.164X
boost-8 0.741 0.902 1.1 3.85X 4.6X 5.5X
Change-Id: I9d611d21310c7b4f93d8e0bc845eb85125abcac9
---
M be/src/runtime/timestamp-test.cc
M be/src/runtime/timestamp-value.cc
2 files changed, 66 insertions(+), 13 deletions(-)
git pull ssh://gerrit.cloudera.org:29418/Impala-ASF refs/changes/82/7082/2
--
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Gerrit-MessageType: newpatchset
Gerrit-Change-Id: I9d611d21310c7b4f93d8e0bc845eb85125abcac9
Gerrit-PatchSet: 2
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: Matthew Jacobs <[email protected]>
Gerrit-Reviewer: Attila Jeges <[email protected]>
Gerrit-Reviewer: Dan Hecht <[email protected]>
Gerrit-Reviewer: Lars Volker <[email protected]>
Gerrit-Reviewer: Marcel Kornacker <[email protected]>
Gerrit-Reviewer: Matthew Jacobs <[email protected]>
Gerrit-Reviewer: Thomas Tauber-Marshall <[email protected]>
