[infinispan-dev] Consolidating temporary per-key data

[Dan Berindei]

The first problem that comes to mind is that context entries are also
stored in a map, at least in transactional mode. So access through the
context would only be faster in non-tx caches, in tx caches it would
not add any benefits.

I also have some trouble imagining how these temporary entries would
be released, since locks, L1 requestors, L1 synchronizers, and write
registrations all have their own rules for cleaning up.

Finally, I'm not sure how much this would help. I actually removed the
write registration for everything except RemoveExpiredCommand when
testing the HotRod server performance, but I didn't get any
significant improvement on my machine. Which was kind of expected,
since the benchmark doesn't seem to be CPU-bound, and JFR was showing
it with < 1.5% of CPU.

Cheers
Dan


On Fri, Nov 27, 2015 at 11:28 AM, Radim Vansa <rvansa at redhat.com> wrote:
> No thoughts at all? @wburns, could I have your view on this?
>
> Thanks
>
> Radim
>
> On 11/23/2015 04:26 PM, Radim Vansa wrote:
>> Hi again,
>>
>> examining some flamegraphs I've found out that recently the
>> ExpirationInterceptor has been added, which registers ongoing write in a
>> hashmap. So at this point we have a map for locks, map for writes used
>> for expiration, another two key-addressed maps in L1ManagerImpl and one
>> in L1NonTxInterceptor and maybe another maps elsewhere.
>>
>> This makes me think that we could spare map lookups and expensive writes
>> by providing *single map for temporary per-key data*. A reference to the
>> entry could be stored in the context to save the lookups. An extreme
>> case would be to put this into DataContainer, but I think that this
>> would prove too tricky in practice.
>>
>> A downside would be the loss of encapsulation (any component could
>> theoretically access e.g. locks), but I don't find that too dramatic.
>>
>> WDYT?
>>
>> Radim
>>
>
>
> --
> Radim Vansa <rvansa at redhat.com>
> JBoss Performance Team
>
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