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  1. MariaDB Server
  2. MDEV-6693

Atomic operations with explicit memory barrier

        Details

        • Type: Task
        • Status: Closed
        • Priority: Major
        • Resolution: Fixed
        • Fix Version/s: 10.1.1
        • Component/s: OTHER
        • Labels:
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          Description

          Currently atomic operations create full memory barrier. This ensures correct program behavior. However weaker memory barriers have lower performance impact and there are many cases when weaker memory barrier is sufficient.

          The idea of this task is to adopt C11 atomic API to some extent, so it is possible to specify memory barriers for atomic operations.

          C11 atomic operations as such seem to be unavailable in many environments. E.g. they appeared only in gcc-4.9. MSVC doesn't seem to support them, same for Solaris Studio.

          It is proposed to use gcc atomic builtins whenever they're available, otherwise fall back to atomic operations with implicit full memory barrier.

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                relates to

                Task - A task that needs to be done. MDEV-6906 Relaxed memory order for counters

                • Major - Major loss of function.
                • Closed

                Epic - Created by JIRA Agile - do not edit or delete. Issue type for a big user story that needs to be broken down. MDEV-6478 MariaDB on Power8

                • Major - Major loss of function.
                • Open
                links to

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                  svoj Sergey Vojtovich added a comment -

                  Sergei, please review patch for this task. It is committed against 10.0, I will leave up to you to decide into which version it is supposed to be pushed to.

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                  svoj Sergey Vojtovich added a comment - Sergei, please review patch for this task. It is committed against 10.0, I will leave up to you to decide into which version it is supposed to be pushed to.
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                  serg Sergei Golubchik added a comment -

                  ok to push (in 10.1)

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                  serg Sergei Golubchik added a comment - ok to push (in 10.1)
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                  svoj Sergey Vojtovich added a comment -

                  Pushed to 10.1.1:

                  commit e813f9b9b3a087910b94ffeda968b53f9fca4311
Author: Sergey Vojtovich <svoj@mariadb.org>
Date:   Tue Oct 14 14:58:35 2014 +0400

    MDEV-6693 - Atomic operations with explicit memory barrier

    Added API for atomic operations with explicit memory barrier. Only gcc
    atomic builtins are currently supported. If they're unavailable, fall
    back to atomic operations with implicit full memory barrier.
                  Show
                  svoj Sergey Vojtovich added a comment - Pushed to 10.1.1: commit e813f9b9b3a087910b94ffeda968b53f9fca4311 Author: Sergey Vojtovich <svoj@mariadb.org> Date: Tue Oct 14 14:58:35 2014 +0400 MDEV-6693 - Atomic operations with explicit memory barrier Added API for atomic operations with explicit memory barrier. Only gcc atomic builtins are currently supported. If they're unavailable, fall back to atomic operations with implicit full memory barrier.

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                    • Assignee:
                      svoj Sergey Vojtovich
                      Reporter:
                      svoj Sergey Vojtovich
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                        Updated:
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