P4080DS Srio performance issue

andrewesterholz — Thu, 31 Aug 2017 05:12:26 GMT

Hello,

I´ve a performance problem writing to a SRIO (1x lane) device using outbound window with NWRITE.

When I write to the outbound window all data transmitted correct to the device but the speed is very slow.

A loop writing 200 32 Bit values (800 Byte) to the outbound window takes about 46 µs.

uint32_t *OutboundAddr =...;

for(i = 0; i < 200; i++)
{
*OutboundAddr = 123;
}

SRIO is configured to have 2.5 GBit so I would expect a time ~3.2 µs

The other direction (device to Inbound window) works much better. Here transmission time is very near to the theoretical value.

Currently I don´t understand why the the NWRITE to the outbound window is so slow.

Best regards

Andre

topic P4080DS Srio performance issue in P-Series