Hal Rosenstock wrote:
On Tue, 2005-09-20 at 19:22, Arlin Davis wrote:
I just noticed some RDMA read performance issues that seem to be related
to the QP starting sequence number. If I set the starting sequence to 1
then all is fine but if I set it to 0x10000 then it seems to add ~40us
to my 32KB RDMA read operation (polling for completions). Has anyone
seen anything like this?
I am running a PCI-e HCA adapter in a EM64T server.
RDMA writes and message sends seem to be unaffected.
What application/ULP are you running ?
He's running a modified version of dtest over DAPL that times RDMA reads from
the post time to poll CQ completion.
The test setup is actually a little more complex. The latencies for the runs
with the various PSNs were:
1 - 60us
0x10000 - 60us (first run)
0x10000 - 100us (subsequent runs)
0x20000 - 100us (first run)
0x20000 - 140us (subsequent runs)
0x40000 - 140us (first run)
0x40000 - 220us (subsequent runs)
The application halts and is re-started between each run, and the QP is
different each time. The only change from run to run is the PSN.
- Sean
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