Re: [PATCH 2/2 net-next] tcp: sk_add_backlog() is too agressive for TCP

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

On Mon, 2012-04-23 at 16:01 -0400, David Miller wrote:

> Hmmm... why don't we just acknowledge reality and special case ACKs?

Yes why not.

> If a TCP packet is dataless we should just let it go through no matter
> what and with no limits.  It is by definition transient and will not
> get queued up into the socket past this backlog stage.

Even being transient we need a limit. Without copybreak, an ACK can cost
2048+256 bytes.

In my 10Gbit tests (standard netperf using 16K buffers), I've seen
backlogs of 300 ACK packets...

> This proposed patch allows non-dataless packets to eat more space in
> the backlog, thus the concern and slight pushback.  And from another
> perspective, having the stack process data packets which will just
> get dropped when we try to attach it to the receive queue is just
> wasted work.

We could try to coalesce ACKs before backlogging them. I'll work on


To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at

[Linux Kernel Discussion]     [Ethernet Bridging]     [Linux Wireless Networking]     [Linux Bluetooth Networking]     [Linux Networking Users]     [VLAN]     [Git]     [IETF Annouce]     [Linux Assembly]     [Security]     [Bugtraq]     [Photo]     [Singles Social Networking]     [Yosemite Information]     [MIPS Linux]     [ARM Linux Kernel]     [ARM Linux]     [Linux Virtualization]     [Linux Security]     [Linux IDE]     [Linux RAID]     [Linux SCSI]     [Free Dating]

Add to Google Powered by Linux