Peng, can you please send version with buffers pool to the list. Might
be something wrong in implementation.
Maxim.
On 12/08/2015 14:42, Bill Fischofer wrote:
This is an interesting topic. I'd like to discuss this a bit during
today's ODP public call.
I think the issue is that while a ring is a very useful implementation
construct its semantics are very SW centric. Perhaps there's
opportunity here for a new Queue type that would permit an
implementation to implement the queue API as a ring for additional
performance? The scheduler itself could use this since its use of
queues is subject to the same issues.
On Mon, Dec 7, 2015 at 11:39 PM, HePeng <xnhp0...@icloud.com
<mailto:xnhp0...@icloud.com>> wrote:
Hi Maxim,
I implement a new version of cuckoo hash based on the ODP
buffer/pool.
As I’ve mentioned earlier, the use of ring in cuckoo hash
is like to the use of
a container, e.g. a queue in C++ STL. In current ODP
implementation, I found that
the ODP queue is implemented more likely a facility for
transmitting objects, not
a container to store objects. Look at the ODP queue enqueue interface:
int odp_queue_enq(odp_queue_t queue, odp_event_t ev);
the *odp_event_t* is related to the events, but I only want to use
odp_queue to
storing and retrieving objects, any objects.
So I use ODP buffer/pool interfaces instead of ODP queue
for the new cuckoo hash implementation.
However, compared to the previous implementation based on
ring, this version
suffers a serious performance degradation. The evaluation is
carried out on a Intel
servers. I test lookup time for 1000 lookups on a table storing 1
million items.
The ODP buffer/pool version suffers at least a 2x performance
degradation.
This is the buffer/pool version, for 1M insert, and 1000 lookup time:
Average insert time = 2.383836, lookup time = 0.000353,
This is the ring version.
Average insert time = 1.629115, lookup time = 0.000098
This performance degradation stems from the heavy
implementation of
ODP buffer/pool. In the ring based one, all the key is stored in
a big array, and
the ring only stores the array indexes of each key. Keys are
retrieved using array indexes.
In the new one, I use ODP buffer to store the key content. Keys
are retrieved by
dereferencing a *odp_buffer_t* handle.
With this high performance degradation, I suggest moving
ring into the odp/api
as a container implementation, and use the previous implementation
of cuckoo hash.
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