You are here: GSI Wiki>DABC Web>DabcTest1 (2007-11-13, HansEssel)EditAttach

DABC tests, July 10

This is first performance tests, done with DABC framework. For the moment we are using our 4-nodes InfiniBand cluster, where verbs and sockets can be tested.

Chaotic tests with verbs & sockets

This is a simplest posible test, where on each node runs two modules - Sender and Receiver. Each Sender connected with all remote receivers (on 4-node system there are 3 connection). Sender sends packet sequentially to each node - one after another. Therefore, if one node blocks, complete module will be blocked, waiting when connection will be active again. All connections used in unidirectional mode when data transported from sender to receiver.

Buffer size Verbs with ackn Verbs without ackn Socket with ackn Socket without akcn
Bytes/us CPU,% Bytes/us CPU,% Bytes/us CPU,% Bytes/us CPU,%
2K 142 48 140 46 35 17 38 81
4K 260 45 200 45 52 16 49 72
8K 479 48 330 46 58 14 67 56
16K 758 48 780 48 61 17 66 34
32K 852 47 928 47 62 24 73 34
64K 900 37 944 37 66 26 74 30
128K 927 21 952 20 56 17 69 20

CPU utilisation given for both CPU. For verbs, seems to be, the only CPU is really busy. In case of socket, both CPU are involved. For socket there is slow down for large packet. It can be explained by chaotic nature of the transfer and a fact, that blocking mode used to recieve/send data. Hopefully, with non-blocking mode, better results will be achieved.

BNet prototype

This is test with more components. There are 4 readout modules, all connected to subevent combiner module. Subevent combiner produces subevents and deliver them to sender module. Sender connected to all receiver modules (including receiver on the same node). Receiver module delivers all packets to event builder, where event is build, and finally event comes to event filter, where all events are rejected. All modules distributed between two threads.

Buffer size Verbs with ackn Verbs without ackn Socket with ackn Socket without akcn
Bytes/us CPU,% Bytes/us CPU,% Bytes/us CPU,% Bytes/us CPU,%
2K - - 69 48 - - 28 26
4K - - 134 48 - - 40 22
8K - - 269 48 - - 52 20
16K - - 577 48 - - 65 15
32K - - 926 49 - - 70 15
64K - - 920 48 - - 73 18
128K - - 937 27 - - 71 28

Results little bit worse compare to pure chaotic test. Here already plays a role of back-pressure approach, while all modules block (not reading) inputs, when they cannot deliver data to outputs. As a result, transfer rate over all connections very similar, while with chaotic tests deviation between nodes can be about 10%.

-- LinevSergey - 10 Jul 2007
Topic revision: r3 - 2007-11-13, HansEssel
 
This site is powered by FoswikiCopyright © by the contributing authors. All material on this collaboration platform is the property of the contributing authors.
Ideas, requests, problems regarding GSI Wiki? Send feedback
Imprint (in German)
Privacy Policy (in German)