rpc_workers default value ignores setting of api_workers

[Adam Spiers]

The help for the rpc_workers config option is:

    Number of RPC worker processes for service. If not specified, the
    default is equal to half the number of API workers.

However, this does not accurately describe the current behaviour, which is to default to half the _default_ number of API workers. This can make a big difference; for example on a 256-CPU machine with 256GB of RAM which has api_workers configured to 8 but rpc_workers not configured to anything, this will result in 64 RPC workers, which is 8 for every API worker!

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/674125

[Adam Spiers (adam.spiers)]

Should be fixed by https://review.opendev.org/#/c/674125/

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/stein
Review: https://review.opendev.org/674227

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/674125
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=61d149c0123997accc5c48994d7a4d1514eb49c9
Submitter: Zuul
Branch: master

commit 61d149c0123997accc5c48994d7a4d1514eb49c9
Author: Adam Spiers <email address hidden>
Date: Thu Aug 1 20:37:09 2019 +0100

    Fix default RPC worker count

    The help for the rpc_workers config option is:

        Number of RPC worker processes for service. If not specified, the
        default is equal to half the number of API workers.

    However, this does not accurately describe the current behaviour,
    which is to default to half the _default_ number of API workers. This
    can make a big difference; for example on a 256-CPU machine with 256GB
    of RAM which has api_workers configured to 8 but rpc_workers not
    configured to anything, this will result in 64 RPC workers, which is 8
    for every API worker!

    Therefore tweak the default to rely on the actual value of
    api_workers, which may be different than the default value.

    Change-Id: I26115932ef4775f157297be1637ee26a4fca4666
    Related-Bug: #1838688
    Closes-Bug: #1838689

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/674227
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=2e7dd4db88a37726ed71e3e9215b7392a1aa9c42
Submitter: Zuul
Branch: stable/stein

commit 2e7dd4db88a37726ed71e3e9215b7392a1aa9c42
Author: Adam Spiers <email address hidden>
Date: Thu Aug 1 20:37:09 2019 +0100

    Fix default RPC worker count

    The help for the rpc_workers config option is:

        Number of RPC worker processes for service. If not specified, the
        default is equal to half the number of API workers.

    However, this does not accurately describe the current behaviour,
    which is to default to half the _default_ number of API workers. This
    can make a big difference; for example on a 256-CPU machine with 256GB
    of RAM which has api_workers configured to 8 but rpc_workers not
    configured to anything, this will result in 64 RPC workers, which is 8
    for every API worker!

    Therefore tweak the default to rely on the actual value of
    api_workers, which may be different than the default value.

    Change-Id: I26115932ef4775f157297be1637ee26a4fca4666
    Related-Bug: #1838688
    Closes-Bug: #1838689
    (cherry picked from commit 61d149c0123997accc5c48994d7a4d1514eb49c9)

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/neutron 15.0.0.0b1 development milestone.

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/neutron 14.0.3 release.