[Oneiric PATCH 0/1] boot speed: ACPI init

Andy Whitcroft apw at canonical.com
Fri Sep 23 15:50:26 UTC 2011

We have recently done a review of the kernel boot time, this is the time
between bios handing off to the kernel and the kernel handing off to
userspace.  We have found a significant regression in ACPI initialisation
which (on atom at least) accounts for close to half of the total kernel
init time.  By shifting acpi_init to using full RCU for its mappings we are
able to halve ACPI initialisation and drop overall kernel initialisation
by 0.25s.  This brings us back close to budget.

If we would like more bake time for this patch it could simply wait
until after release for the first uploada as there is not functional
issue fixed by this patch.

Proposing for Oneiric.


Andy Whitcroft (1):
  acpi_init: move to full RCU free for IO mappings

 drivers/acpi/atomicio.c |   12 +++++++++---
 drivers/acpi/osl.c      |   16 +++++++++++-----
 2 files changed, 20 insertions(+), 8 deletions(-)


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