[dpdk-dev] [PATCH v3 1/6] eal: add power management intrinsics

Stephen Hemminger stephen at networkplumber.org
Fri Sep 4 20:42:37 CEST 2020


On Fri,  4 Sep 2020 11:18:55 +0100
Liang Ma <liang.j.ma at intel.com> wrote:

> Add two new power management intrinsics, and provide an implementation
> in eal/x86 based on UMONITOR/UMWAIT instructions. The instructions
> are implemented as raw byte opcodes because there is not yet widespread
> compiler support for these instructions.
> 
> The power management instructions provide an architecture-specific
> function to either wait until a specified TSC timestamp is reached, or
> optionally wait until either a TSC timestamp is reached or a memory
> location is written to. The monitor function also provides an optional
> comparison, to avoid sleeping when the expected write has already
> happened, and no more writes are expected.
> 
> Signed-off-by: Liang Ma <liang.j.ma at intel.com>
> Signed-off-by: Anatoly Burakov <anatoly.burakov at intel.com>

Before this is merged, please work with Arm maintainers to have a version that
works on Arm 64 as well. Don't think this should be merged unless the two major
platforms supported by DPDK can work with it.

Also, not sure if this mechanism can work with other drivers. You need to
work with other vendors to show that the same infrastructure can work with
their hardware. Once again, I don't think this can go in if it only can
work on Intel.  It needs to work on Broadcom, Mellanox to be useful.

Will it work in a VM? Will it work with virtio or vmxnet3?

Having a single vendor solution is a non-starter for me.
They don't all have to be there to get it merged, but if the design only
works on single platform then it is not helpful.


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