Red Hat Bugzilla – Bug 446136
RHEL4.8: enable deep C states on Nehalem for idle efficiency
Last modified: 2015-05-08 10:02:10 EDT
1. Feature Name: enable deep C states for Nehalem
Because RH is getting some late pressure from OEMs and customers for
TylersburgEP/Nehalem support in 4.7, I'm concerned that this might be required.
We had intended only to submit it for 5.3, but I now plan to look at it ASAP in
the 4.7 context.
This patch that went upstream in June 2007 gives a a 16x improvement in
efficiency at idle on Nehalem chips.
Architectures (mark all that apply)
x 32-bit x86
x 64-bit Intel EM64T
Priority (H,M,L): H
Target Release Date:
Drivers or hardware dependency:
3. Business Justification:
a. Why is this feature needed?
Big power efficiency improvement
b. What hardware does this enable?
c. Forecast, volume or high end platform?
d. Any configuration info?
e. When needed?
f. Are there other dependencies (drivers).
a. Is code accepted upstream? If so, what version or patch?
5. Hardware to Red Hat? Red Hat can't integrate/test features without hardware.
Yes, two alpha Tylersburg EP and one Tylersburg HEDT are already at RH, more coming.
6. Partner management contact, email, phone, chat
7. Partner technical contact, email, phone, chat
The Nehalem processor is integral to the Tylersburg-EP platform that all of the
OEMs will be planning. Moreover, the deep c-states improves the overall power
efficiency of idle CPUs, which many customers are very interested in.
This request is not going to be addressed in RHEL 4.7. Moving to 4.8.
John, is 443516 dup of this BZ?
John, never mind! 443516 is the 5.3 equivalent.
It has been decided that this bug will be to intrusive to fix for RHEL 4.x. We will only support deep c-states in RHEL 5.3 and beyond.