The new flag, -c <period>, sets the interrupt coalescing period in
microseconds through the new ioat(4) API ioat_set_interrupt_coalesce().
Also add a -z flag to zero ioat statistics before tests, to make it easy
to measure results.
Sponsored by: EMC / Isilon Storage Division
Allows DMA from/to arbitrary KVA or physical address. /dev/ioat_test
must be enabled by root and is only R/W root, so this is approximately
as dangerous as /dev/mem and /dev/kmem.
Sponsored by: EMC / Isilon Storage Division
The IOAT hardware supports writing a 64-bit pattern to some destination
buffer. The same limitations on buffer length apply as for copy
operations. Throughput is a bit higher (probably because fill does not
have to spend bandwidth reading from a source in memory).
Support for testing Block Fill has been added to ioatcontrol(8) and the
ioat_test device. ioatcontrol(8) accepts the '-f' flag, which tests
Block Fill. (If the flag is omitted, the tool tests copy by default.)
The '-V' flag, in conjunction with '-f', verifies that buffers are
filled in the expected pattern.
Tested on: Broadwell DE (Xeon D-1500)
Sponsored by: EMC / Isilon Storage Division
The test logic now preallocates memory before running the test.
The buffer size is now configurable. Post-copy verification is
configurable. The number of copies to chain into one transaction (one
interrupt) is configurable.
A 'duration' mode is added, which repeats the test until the duration
has elapsed, reporting the B/s and transactions completed.
ioatcontrol.8 has been updated to document the new arguments.
Initial limits (on this particular Broadwell-DE) (and when the
interrupts are working) seem to be: 256 interrupts/sec or ~6 GB/s,
whichever limit is more restrictive.
Unfortunately, it seems the interrupt-reset handling on Broadwell isn't
working as intended. That will be fixed in a later commit.
Sponsored by: EMC / Isilon Storage Division
I/OAT is also referred to as Crystal Beach DMA and is a Platform Storage
Extension (PSE) on some Intel server platforms.
This driver currently supports DMA descriptors only and is part of a
larger effort to upstream an interconnect between multiple systems using
the Non-Transparent Bridge (NTB) PSE.
For now, this driver is only built on AMD64 platforms. It may be ported
to work on i386 later, if that is desired. The hardware is exclusive to
x86.
Further documentation on ioat(4), including API documentation and usage,
can be found in the new manual page.
Bring in a test tool, ioatcontrol(8), in tools/tools/ioat. The test
tool is not hooked up to the build and is not intended for end users.
Submitted by: jimharris, Carl Delsey <carl.r.delsey@intel.com>
Reviewed by: jimharris (reviewed my changes)
Approved by: markj (mentor)
Relnotes: yes
Sponsored by: Intel
Sponsored by: EMC / Isilon Storage Division
Differential Revision: https://reviews.freebsd.org/D3456
