On 2/6/2018 10:54 AM, Or Gerlitz wrote:
On Tue, Feb 6, 2018 at 12:03 AM, Sagi Grimberg <sagi@xxxxxxxxxxx> wrote:
The main reason why this implementation is different then the common networking devices
implementation (and kept separate) is that in my mind at least, network devices are different
animals than other I/O devices in the sense that:
Oh, I see now that you do refer to the netdev library, I was confused
by "In the networking stack, each device driver
implements adaptive IRQ moderation on its own" comment.
(a) network devices rely heavily on byte count of raw ethernet frames for adaptive moderation
while in storage or I/O, the byte count is often a result of a submission/completion transaction
and sometimes even known only to the application on top of the infrastructure (like in the
rdma case).
(b) Performance characteristics and expectations in representative workloads.
(c) network devices collect all sort of stats for different functionalities (where adaptive moderation
is only one use-case) and I'm not sure at all that a subset of stats could easily migrate to a different
context.
I think Tal has idea/s on how the existing library can be changed to
support more modes/models
What I was thinking is allowing DIM algorithm to disregard data which is
0. Currently if bytes == 0 we return "SAME" immediately. We can change
it to simply move to the packets check (which may be renamed to
"completions"). This way you could use DIM while only optimizing to (P1)
high packet rate and (P2) low interrupt rate.
