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| author | Keir Fraser <keir.fraser@citrix.com> | 2009-12-14 07:54:53 +0000 |
|---|---|---|
| committer | Keir Fraser <keir.fraser@citrix.com> | 2009-12-14 07:54:53 +0000 |
| commit | 3535332327305778c02ac1a8fc49bec29e842b20 (patch) | |
| tree | 699ac03b5769fd7d7a8be3573a23f50700e0ad38 /xen/include/xen/cpuidle.h | |
| parent | 018b6522ced796ef149bb2063db2d3d3643f17f1 (diff) | |
| download | xen-3535332327305778c02ac1a8fc49bec29e842b20.tar.gz xen-3535332327305778c02ac1a8fc49bec29e842b20.tar.bz2 xen-3535332327305778c02ac1a8fc49bec29e842b20.zip | |
cpuidle: fix the menu governor to enhance IO performance
this is a revised version of linux upstream commit
69d25870f20c4b2563304f2b79c5300dd60a067e:
"
cpuidle: fix the menu governor to boost IO performance
Fix the menu idle governor which balances power savings, energy
efficiency
and performance impact.
The reason for a reworked governor is that there have been
serious
performance issues reported with the existing code on Nehalem
server
systems.
To show this I'm sure Andrew wants to see benchmark results:
(benchmark is "fio", "no cstates" is using "idle=3Dpoll")
no cstates current linux new algorithm
1 disk 107 Mb/s 85 Mb/s 105 Mb/s
2 disks 215 Mb/s 123 Mb/s 209 Mb/s
12 disks 590 Mb/s 320 Mb/s 585 Mb/s
In various power benchmark measurements, no degredation was found
by our
measurement&diagnostics team. Obviously a small percentage more
power was
used in the "fio" benchmark, due to the much higher performance.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Cc: Len Brown <lenb@kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Yanmin Zhang <yanmin_zhang@linux.intel.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
"
in Xen version, most logic is similar and with only one exception:
linux use nr_iowait and loadavg to track the pending I/O request,
which however is not visible to Xen. so Xen use the do_irq frequency
to estimate the I/O pressure. this is not as accurate as linux, and
the better approach is to convey guest latency requirement to
hypervisor by virtual C state. this can be the future enhancement.
the detail algorithm description is in code comment. with this new
algorithm, fio benchmark performance improve ~5% with 1 disk. and no
power degration is found in idle case.
Signed-off-by: Yu Ke <ke.yu@intel.com>
Diffstat (limited to 'xen/include/xen/cpuidle.h')
| -rw-r--r-- | xen/include/xen/cpuidle.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/xen/include/xen/cpuidle.h b/xen/include/xen/cpuidle.h index edf1ce6fb2..4f4a2995ca 100644 --- a/xen/include/xen/cpuidle.h +++ b/xen/include/xen/cpuidle.h @@ -86,4 +86,6 @@ struct cpuidle_governor extern struct cpuidle_governor *cpuidle_current_governor; void cpuidle_disable_deep_cstate(void); +#define CPUIDLE_DRIVER_STATE_START 1 + #endif /* _XEN_CPUIDLE_H */ |