maria-developers team mailing list archive

[MARK CALLAGHAN <mdcallag@xxxxxxxxx>]

This is good news. Don't forget to have someone write a blog post about it.


On Tue, Jan 21, 2014 at 7:04 AM, Michael Widenius <monty@xxxxxxxxxxxx>wrote:

>
> Hi!
>
> >>>>> "Sergey" == Sergey Vojtovich <svoj@xxxxxxxxxxx> writes:
>
> Sergey> Hi Mark,
> Sergey> we identified a few single-thread performance issues during the
> Barcelona
> Sergey> meeting. Monty should have them fixed in his private tree. Fixes
> are quite
> Sergey> generic and should improve performance almost in all cases. An
> exception is
> Sergey> bottlenecks specific to certain use cases.
>
> A short followup of the above:
>
> While testing trivial queries, we noticed some code paths at top that
> should not be there:
> - Mallocs (simple queries should be run without any mallocs).
>   - I managed to remove some of them.
> - Some atomic increments/sum could be avoided.
>   (For simple SELECT * FROM empty_table, an atomic increment could
>   take almost 1% of execution time)
>   - This was fixed by marking more memory as THREAD_SPECIFIC and not
>     do atomic operations on these until SHOW STATUS
> - Lots of calls to current_thd
>   - A large portion of these calls are now removed.
> - Some byte rotate operations where slower than expected.  These was often
>   used in Aria tables and MyISAM tables.
>   -  We will replace these with one assembler instructions for X64
>      ships which will make them MUCH faster.
>
> I have done the above fixed in my 10.0 tree. I just need to finalize
> and benchmark this before I push...
>
> Regards,
> Monty
>



-- 
Mark Callaghan
mdcallag@xxxxxxxxx