kernel_optimize_test/include
Venki Pallipadi bde6f5f59c x86: voluntary leave_mm before entering ACPI C3
Aviod TLB flush IPIs during C3 states by voluntary leave_mm()
before entering C3.

The performance impact of TLB flush on C3 should not be significant with
respect to C3 wakeup latency. Also, CPUs tend to flush TLB in hardware while in
C3 anyways.

On a 8 logical CPU system, running make -j2, the number of tlbflush IPIs goes
down from 40 per second to ~ 0. Total number of interrupts during the run
of this workload was ~1200 per second, which makes it ~3% savings in wakeups.

There was no measurable performance or power impact however.

[ akpm@linux-foundation.org: symbol export fixes. ]

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30 13:32:01 +01:00
..
acpi x86: dummy placeholder for acpi/reboot.h 2008-01-30 13:31:17 +01:00
asm-alpha
asm-arm ext4: Add ext4_find_next_bit() 2008-01-28 23:58:27 -05:00
asm-avr32
asm-blackfin
asm-cris
asm-frv
asm-generic Merge git://git.kernel.org/pub/scm/linux/kernel/git/sam/kbuild 2008-01-29 22:46:14 +11:00
asm-h8300
asm-ia64 x86: voluntary leave_mm before entering ACPI C3 2008-01-30 13:32:01 +01:00
asm-m32r core: remove last users of empty FASTCALL macro 2008-01-30 13:31:17 +01:00
asm-m68k ext4: Add ext4_find_next_bit() 2008-01-28 23:58:27 -05:00
asm-m68knommu ext4: Add ext4_find_next_bit() 2008-01-28 23:58:27 -05:00
asm-mips [MIPS] Malta, Atlas: move an extern function declaration to the header file 2008-01-29 10:15:05 +00:00
asm-parisc
asm-powerpc powerpc: arch_has_single_step 2008-01-30 13:30:51 +01:00
asm-ppc
asm-s390 ext4: Add ext4_find_next_bit() 2008-01-28 23:58:27 -05:00
asm-sh
asm-sparc
asm-sparc64
asm-um uml: add asm-um/asm.h 2008-01-30 13:31:17 +01:00
asm-v850
asm-x86 x86: voluntary leave_mm before entering ACPI C3 2008-01-30 13:32:01 +01:00
asm-xtensa
crypto
keys
linux x86: x86 core dump TLS 2008-01-30 13:31:56 +01:00
math-emu
media
mtd
net [NET_SCHED]: act_api: use PTR_ERR in tcf_action_init/tcf_action_get 2008-01-28 15:11:17 -08:00
pcmcia
rdma
rxrpc
scsi
sound
video
xen
Kbuild