The blockchain that provides the digital content namespace for the LBRY protocol
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Wladimir J. van der Laan becd8dd2ec
Merge #12618: Set SCHED_BATCH priority on the loadblk thread.
d54874d Set SCHED_BATCH priority on the loadblk thread. (Evan Klitzke)

Pull request description:

  Today I came across #10271, and while reading the discussion #6358 was linked to. Linux systems have a `SCHED_BATCH` scheduler priority that is useful for threads like loadblk. You can find the full details at [sched(7)](http://man7.org/linux/man-pages/man7/sched.7.html), but I'll quote the relevant part of the man page below:

  > ...this policy will cause the scheduler to always assume that the thread is
  CPU-intensive. Consequently, the scheduler will apply a small scheduling penalty
  with respect to wakeup behavior, so that this thread is mildly disfavored in
  scheduling decisions.
  >
  > This policy is useful for workloads that are noninteractive, but do not want to
  lower their nice value, and for workloads that want a deterministic scheduling
  policy without interactivity causing extra preemptions (between the workload's
  tasks).

  I think this change is useful independently of #10271 and irrespective of whether that change is merged. Under normal operation the loadblk thread will just import `mempool.dat`. However, if Bitcoin is started with `-reindex` or `-reindex-chainstate` this thread will use a great deal of CPU while it rebuilds the chainstate database (and the block database in the case of `-reindex`). By setting `SCHED_BATCH` this thread is less likely to interfere with interactive tasks (e.g. the user's web browser, text editor, etc.).

  I'm leaving the nice value unchanged (which also affects scheduling decisions) because I think that's better set by the user. Likewise I'm not using [ioprio_set(2)](http://man7.org/linux/man-pages/man2/ioprio_set.2.html) because it can cause the thread to become completely I/O starved (and knowledgeable users can use `ionice(1)` anyway).

Tree-SHA512: ea8f7d3921ed5708948809da771345cdc33efd7ba3323e9dfec07a25bc21e8612e2676f9c178e2710c7bc437e8c9cafc5e0463613688fea5699b6e8e2fec6cff
2018-04-07 19:48:39 +02:00
.github Make default issue text all comments to make issues more readable 2017-11-16 11:50:56 -05:00
.tx tx: Update transifex slug for 0.16 2018-01-24 16:35:40 +01:00
build-aux/m4 ax_boost_{chrono,unit_test_framework}.m4: take changes from upstream 2018-03-15 19:59:11 +01:00
contrib Merge #12708: Make verify-commits.sh test that merges are clean 2018-04-07 18:48:27 +02:00
depends Merge #12625: depends: biplist 1.0.3 2018-03-14 14:29:27 +01:00
doc Merge #12860: Add testmempoolaccept to release-notes, Add missing const 2018-04-07 18:43:39 +02:00
share Change all python files to use Python3 2018-03-26 16:49:33 -04:00
src Merge #12618: Set SCHED_BATCH priority on the loadblk thread. 2018-04-07 19:48:39 +02:00
test Merge #12849: Tests: Add logging in loops in p2p_sendhears.py 2018-04-07 10:33:55 -04:00
.gitattributes Separate protocol versioning from clientversion 2014-10-29 00:24:40 -04:00
.gitignore [build] .gitignore: add QT Creator artifacts 2017-12-22 12:37:00 +01:00
.travis.yml travis: Run verify-commits only on cron jobs 2018-03-31 10:59:59 -04:00
autogen.sh Add MIT license to autogen.sh and share/genbuild.sh 2016-09-21 23:01:36 +00:00
configure.ac Add --with-sanitizers option to configure 2018-03-28 12:33:04 -07:00
CONTRIBUTING.md Docs: Improve documentation on standard communication channels 2018-03-22 12:58:57 -07:00
COPYING [Trivial] Update license year range to 2018 2018-01-01 04:33:09 +09:00
INSTALL.md Update INSTALL landing redirection notice for build instructions. 2016-10-06 12:27:23 +13:00
libbitcoinconsensus.pc.in Unify package name to as few places as possible without major changes 2015-12-14 02:11:10 +00:00
Makefile.am make clean removes src/qt/moc_ files 2018-04-03 15:04:35 +02:00
README.md Docs: Improve documentation on standard communication channels 2018-03-22 12:58:57 -07:00

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