[PATCH 0/3] nvme power saving

From: Andy Lutomirski
Date: Mon Aug 29 2016 - 05:26:04 EST

Hi all-

Here's v1 of the APST patch set. The biggest bikesheddable thing (I
think) is the scaling factor. I currently have it hardcoded so that
we wait 50x the total latency before entering a power saving state.
On my Samsung 950, this means we enter state 3 (70mW, 0.5ms entry
latency, 5ms exit latency) after 275ms and state 4 (5mW, 2ms entry
latency, 22ms exit latency) after 1200ms. I have the default max
latency set to 25ms.

FWIW, in practice, the latency this introduces seems to be well
under 22ms, but my benchmark is a bit silly and I might have
measured it wrong. I certainly haven't observed a slowdown just
using my laptop.

Andy Lutomirski (3):
nvme/scsi: Remove power management support
nvme: Pass pointers, not dma addresses, to nvme_get/set_features()
nvme: Enable autonomous power state transitions

drivers/nvme/host/core.c | 199 +++++++++++++++++++++++++++++++++++++++++++++--
drivers/nvme/host/nvme.h | 10 ++-
drivers/nvme/host/scsi.c | 80 ++-----------------
include/linux/nvme.h | 6 ++
4 files changed, 211 insertions(+), 84 deletions(-)