* Michael Wang <wang...@linux.vnet.ibm.com> wrote:
> v3 change log:
> Fix small logical issues (Thanks to Mike Galbraith).
> Change the way of handling WAKE.
>
> This patch set is trying to simplify the select_task_rq_fair()
> with schedule balance map.
>
> After get rid of the complex code and reorganize the logical,
> pgbench show the improvement, more the clients, bigger the
> improvement.
>
> Prev: Post:
>
> | db_size | clients | | tps | | tps |
> +---------+---------+ +-------+ +-------+
> | 22 MB | 1 | | 10788 | | 10881 |
> | 22 MB | 2 | | 21617 | | 21837 |
> | 22 MB | 4 | | 41597 | | 42645 |
> | 22 MB | 8 | | 54622 | | 57808 |
> | 22 MB | 12 | | 50753 | | 54527 |
> | 22 MB | 16 | | 50433 | | 56368 | +11.77%
> | 22 MB | 24 | | 46725 | | 54319 | +16.25%
> | 22 MB | 32 | | 43498 | | 54650 | +25.64%
> | 7484 MB | 1 | | 7894 | | 8301 |
> | 7484 MB | 2 | | 19477 | | 19622 |
> | 7484 MB | 4 | | 36458 | | 38242 |
> | 7484 MB | 8 | | 48423 | | 50796 |
> | 7484 MB | 12 | | 46042 | | 49938 |
> | 7484 MB | 16 | | 46274 | | 50507 | +9.15%
> | 7484 MB | 24 | | 42583 | | 49175 | +15.48%
> | 7484 MB | 32 | | 36413 | | 49148 | +34.97%
> | 15 GB | 1 | | 7742 | | 7876 |
> | 15 GB | 2 | | 19339 | | 19531 |
> | 15 GB | 4 | | 36072 | | 37389 |
> | 15 GB | 8 | | 48549 | | 50570 |
> | 15 GB | 12 | | 45716 | | 49542 |
> | 15 GB | 16 | | 46127 | | 49647 | +7.63%
> | 15 GB | 24 | | 42539 | | 48639 | +14.34%
> | 15 GB | 32 | | 36038 | | 48560 | +34.75%
>
> Please check the patch for more details about schedule balance map.
The changes look clean and reasoable, any ideas exactly *why* it
speeds up?
I.e. are there one or two key changes in the before/after logic
and scheduling patterns that you can identify as causing the
speedup?
Such changes also typically have a chance to cause regressions
in other workloads - when that happens we need this kind of
information to be able to enact plan-B.
Thanks,
Ingo
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