* [dpdk-dev] About interrupts and packet loss
@ 2013-09-01 7:01 Nulik Nol
2013-09-02 13:25 ` Thomas Monjalon
0 siblings, 1 reply; 2+ messages in thread
From: Nulik Nol @ 2013-09-01 7:01 UTC (permalink / raw)
To: dev
Hi,
I have read in a pdf document about DPDK that the driver that comes
within the DPDK distribution was modified to disable interrupt
handling. This explains why DPDK is so fast.
However , this means the app in user space must constantly watch for
new packets, so the CPU load average will be almost 100% all the time,
correct? Well, then what happens if the app executes a busy process
and at that time all RX rings get filled, will the incoming network
traffic be lost?
Thanks in advance
Nulik
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [dpdk-dev] About interrupts and packet loss
2013-09-01 7:01 [dpdk-dev] About interrupts and packet loss Nulik Nol
@ 2013-09-02 13:25 ` Thomas Monjalon
0 siblings, 0 replies; 2+ messages in thread
From: Thomas Monjalon @ 2013-09-02 13:25 UTC (permalink / raw)
To: Nulik Nol; +Cc: dev
01/09/2013 09:01, Nulik Nol :
> I have read in a pdf document about DPDK that the driver that comes
> within the DPDK distribution was modified to disable interrupt
> handling. This explains why DPDK is so fast.
Yes, DPDK drivers poll the NICs.
> However , this means the app in user space must constantly watch for
> new packets, so the CPU load average will be almost 100% all the time,
> correct? Well, then what happens if the app executes a busy process
> and at that time all RX rings get filled, will the incoming network
> traffic be lost?
It's not specific to DPDK. If CPU don't read packets fast enough in the NIC,
the buffer will be full, and yes, some packets will be lost.
By using DPDK with the right number of CPUs, you can achieve high rates
without loss.
--
Thomas
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