I am sponsoring this case on behalf of Bruce Curtis. It requests Patch
binding, and is being marked as a Closed Approved Automatic as the only
non-private interfaces are new driver names. If anyone belives this is
not a self-review, it can be turned into a fasttrack.
1. Introduction - TCP/IP support for Intel I/OAT hardware
Author: Bruce.Curtis at Sun.COM
Date: 04/11/2008
All new Sun Intel based platforms have Intel I/OAT (I/O Acceleration
Technology) hardware.
The first such hardware is an on-systemboard asynchronous DMA engine
code named Crystal Beach.
Through a set of RFEs Solaris will use this hardware to implement
TCP receive side zero CPU copy via a socket.
This is a transparent implementation, i.e. no user-land application
changes are required. No new APIs are introduced nor any changes to
existing APIs.
2. Type of Release - Patch
This is a patch as this new feature is targeting an S10 update.
3. Project Dependencies - None
This new feature doesn't depend on any other project nor does
any other project depend on it.
4. Project Architecture
The new feature is implemented as specified in 4 RFEs:
6582335 TCP/IP receive-side zero CPU copy for support
of Intel I/OAT hardware
6582330 sodirect - socket direct, for support of Intel
I/OAT hardware
6582323 uioa - uio asynchronous, for support of Intel
I/OAT hardware
6567008 driver for intel ioat v1 & v2 DMA engine needed
Such that a new device driver "ioat" interfaces to the on-board
I/OAT asynchronous DMA chip, the pseudo driver "dcopy" interfaces
to the "ioat" driver, the uioa (uioa asynchronous) extensions to
uio (user i/o) interfaces to dcopy, and lastly sockfs and tcp are
modified to setup and use sodirect (socket direct) and uioa when
a socket read()/recv() system call is made and I/OAT hardware is
present and the user buffer is of sufficent size.
Then, TCP payload data copy is accomplished via a DMA by the
NIC (as it is for non I/OAT) into a kernel mblk_t's dblk_t data
buffer then early in TCP payload processing a 2nd DMA is
started from the dblk_t data buffer to the user-land buffer
specified and the dblk_t is marked as such.
The mblk_t is processed by the network stack framework as
usual but before the read()/recv() returns sockfs checks for
the I/OAT DMA completion.
5. Public Interfaces - SUNWdcopy, sys/sodirect.h
Package contains the "ioat" device driver and "dcopy" pseudo
driver.
A new include file "sys/sodirect.h" is added to the SUNWhea
package as it is included by "sys/sonode.h" and "sys/uio.h".
6. Interface Specification
The commitment level for "SUNWdcopy" and the driver names
"ioat" and "dcopy" are: stable
The include file "sys/sodirect.h", and any interfaces contained
there in, are: project private
7. Resources and Schedule
7.4. Steering Committee requested information
7.4.1. Consolidation C-team Name:
ON
7.5. ARC review type: Automatic
7.6. ARC Exposure: open
