[v2] util/thread-pool: Expose minimun and maximum size

[PATCH v2 0/4] util/thread-pool: Expose minimun and maximum size

Nicolas Saenz Julienne posted 4 patches 2 years, 1 month ago

Diff against v1 v3 v4 v5 v6
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git fetch https://github.com/patchew-project/qemu tags/patchew/20220303145822.518887-1-nsaenzju@redhat.com

Maintainers: Stefan Hajnoczi <stefanha@redhat.com>, Fam Zheng <fam@euphon.net>, Kevin Wolf <kwolf@redhat.com>, Hanna Reitz <hreitz@redhat.com>, Paolo Bonzini <pbonzini@redhat.com>, "Daniel P. Berrangé" <berrange@redhat.com>, Eduardo Habkost <eduardo@habkost.net>, Eric Blake <eblake@redhat.com>, Markus Armbruster <armbru@redhat.com>

There is a newer version of this series

event-loop-base.c                | 140 +++++++++++++++++++++++++++++++
include/block/aio.h              |  10 +++
include/block/thread-pool.h      |   3 +
include/qemu/main-loop.h         |  10 +++
include/sysemu/event-loop-base.h |  41 +++++++++
include/sysemu/iothread.h        |   6 +-
iothread.c                       |  68 +++++----------
meson.build                      |  26 +++---
qapi/qom.json                    |  36 +++++++-
util/aio-posix.c                 |   1 +
util/async.c                     |  20 +++++
util/main-loop.c                 |  65 ++++++++++++++
util/thread-pool.c               |  61 +++++++++++++-
13 files changed, 422 insertions(+), 65 deletions(-)
create mode 100644 event-loop-base.c
create mode 100644 include/sysemu/event-loop-base.h

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[PATCH v2 0/4] util/thread-pool: Expose minimun and maximum size

Posted by Nicolas Saenz Julienne 2 years, 1 month ago

As discussed on the previous RFC[1] the thread-pool's dynamic thread
management doesn't play well with real-time and latency sensitive
systems. This series introduces a set of controls that'll permit
achieving more deterministic behaviours, for example by fixing the
pool's size.

We first introduce a new common interface to event loop configuration by
moving iothread's already available properties into an abstract class
called 'EventLooopBackend' and have both 'IOThread' and the newly
created 'MainLoop' inherit the properties from that class.

With this new configuration interface in place it's relatively simple to
introduce new options to fix the even loop's thread pool sizes. The
resulting QAPI looks like this:

    -object main-loop,id=main-loop,thread-pool-min=1,thread-pool-max=1

Note that all patches are bisect friendly and pass all the tests.

[1] https://patchwork.ozlabs.org/project/qemu-devel/patch/20220202175234.656711-1-nsaenzju@redhat.com/

---
Changes since v1:
 - Address all Stefan's comments
 - Introduce new fix

Nicolas Saenz Julienne (4):
  util/thread-pool: Fix thread pool freeing locking
  Introduce event-loop-base abstract class
  util/main-loop: Introduce the main loop into QOM
  util/event-loop-base: Introduce options to set the thread pool size

 event-loop-base.c                | 140 +++++++++++++++++++++++++++++++
 include/block/aio.h              |  10 +++
 include/block/thread-pool.h      |   3 +
 include/qemu/main-loop.h         |  10 +++
 include/sysemu/event-loop-base.h |  41 +++++++++
 include/sysemu/iothread.h        |   6 +-
 iothread.c                       |  68 +++++----------
 meson.build                      |  26 +++---
 qapi/qom.json                    |  36 +++++++-
 util/aio-posix.c                 |   1 +
 util/async.c                     |  20 +++++
 util/main-loop.c                 |  65 ++++++++++++++
 util/thread-pool.c               |  61 +++++++++++++-
 13 files changed, 422 insertions(+), 65 deletions(-)
 create mode 100644 event-loop-base.c
 create mode 100644 include/sysemu/event-loop-base.h

-- 
2.35.1