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1 ms latency in event_send->event_receive


Are you using 68en302...? If so try to ping with BIIIG packets, if the
latency becomes better it means
that your're missing Ethernet interrupts.....


----- Original Message -----
From: <vellu at tatooine.yok.utu.fi>
To: <rtems-list at oarcorp.com>
Cc: <vellu at tatooine.yok.utu.fi>
Sent: Saturday, December 18, 1999 1:17 PM
Subject: 1 ms latency in event_send->event_receive

> I am implementing Ethernet driver with RTEMS 4.0. I have followed your
> guidance from the documents. Driver seems to work stable but I am not
> happy with performance. There seems to be 5 ms latency in ICMP echo (ping)
> for even for very small packets. I have found that this latency is very
> dependent of how many event_send event_receive pairs there is in the
> driver. In my analysis I found that every event_send, event_receive pair
> takes about 1 ms to succeed for example when I am sending event from
> interrupt handler to rxtask. There is only rxtask, txtask, interrupt
> handler in the system and network task (created by BSD stack). All these
> tasks have same priority because they are created by
> rtems_create_network_task in rtems_glue.c. Why is this latency so high?
> I am using processor with Motorola 68K core.
> Veli-Pekka Yl?nen