linux/arch/powerpc/kernel
Anton Blanchard f5f0307f42 powerpc: Improve scheduling of system call entry instructions
After looking at our system call path, Mary Brown suggested that we
should put all mfspr SRR* instructions before any mtspr SRR*.

To test this I used a very simple null syscall (actually getppid)
testcase at http://ozlabs.org/~anton/junkcode/null_syscall.c

I tested with the following changes against the pseries_defconfig:

CONFIG_VIRT_CPU_ACCOUNTING=n
CONFIG_AUDIT=n

to remove the overhead of virtual CPU accounting and syscall
auditing.

POWER6:
baseline:       mean = 757.2 cycles       sd = 2.108
modified:       mean = 759.1 cycles       sd = 2.020

POWER7:
baseline:       mean = 411.4 cycles       sd = 0.138
modified:       mean = 404.1 cycles       sd = 0.109

So we have 1.77% improvement on POWER7 which looks significant. The
POWER6 suggest a 0.25% slowdown, but the results are within 1
standard deviation and may be in the noise.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-05-19 14:30:42 +10:00
..
vdso32 Fix common misspellings 2011-03-31 11:26:23 -03:00
vdso64 Fix common misspellings 2011-03-31 11:26:23 -03:00
.gitignore
align.c powerpc: Remove fpscr use from [kvm_]cvt_{fd,df} 2010-09-02 14:07:32 +10:00
asm-offsets.c powerpc: Per process DSCR + some fixes (try#4) 2011-04-27 14:18:19 +10:00
audit.c
btext.c Fix common misspellings 2011-03-31 11:26:23 -03:00
cacheinfo.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
cacheinfo.h powerpc: Rewrite sysfs processor cache info code 2009-01-08 16:25:10 +11:00
clock.c
compat_audit.c
cpu_setup_6xx.S powerpc: Fix some 6xx/7xxx CPU setup functions 2011-02-07 12:57:11 +11:00
cpu_setup_44x.S powerpc/44x: Add support for the AMCC APM821xx SoC 2010-10-13 08:47:09 -04:00
cpu_setup_a2.S powerpc: Add A2 cpu support 2011-04-27 13:02:02 +10:00
cpu_setup_fsl_booke.S rapidio: modify configuration to support PCI-SRIO controller 2011-03-23 19:46:42 -07:00
cpu_setup_pa6t.S
cpu_setup_power7.S powerpc: Initialize TLB and LPID register on HV mode Power7 2011-04-20 11:03:24 +10:00
cpu_setup_ppc970.S
cputable.c powerpc: Free up some CPU feature bits by moving out MMU-related features 2011-04-27 14:18:52 +10:00
crash_dump.c crash_dump: export is_kdump_kernel to modules, consolidate elfcorehdr_addr, setup_elfcorehdr and saved_max_pfn 2011-03-23 19:47:19 -07:00
crash.c powerpc/kexec: Fix build failure on 32-bit SMP 2011-05-04 15:22:59 +10:00
dbell.c powerpc/book3e: Resend doorbell exceptions to ourself 2010-07-09 16:11:19 +10:00
dma-iommu.c powerpc/iommu: Use coherent_dma_mask for alloc_coherent 2010-12-09 15:17:50 +11:00
dma-swiotlb.c of: Merge of_platform_bus_type with platform_bus_type 2010-07-24 09:57:51 -06:00
dma.c powerpc: Implement dma_mmap_coherent() 2011-03-30 10:44:00 +11:00
e500-pmu.c perf, arch: Cleanup perf-pmu init vs lockup-detector 2010-11-26 15:14:56 +01:00
entry_32.S powerpc/ppc32/tracing: Add stack frame to calls of trace_hardirqs_on/off 2011-01-21 14:08:33 +11:00
entry_64.S powerpc: Free up some CPU feature bits by moving out MMU-related features 2011-04-27 14:18:52 +10:00
exceptions-64e.S powerpc: Add early debug for WSP platforms 2011-05-06 13:32:41 +10:00
exceptions-64s.S powerpc: Improve scheduling of system call entry instructions 2011-05-19 14:30:42 +10:00
firmware.c powerpc: Make powerpc_firmware_features __read_mostly 2010-02-09 13:56:07 +11:00
fpu.S powerpc: Remove second definition of STACK_FRAME_OVERHEAD 2010-11-29 15:48:23 +11:00
fsl_booke_entry_mapping.S powerpc/fsl-booke: Fix address issue when using relocatable kernels 2010-07-11 11:04:08 -05:00
ftrace.c Merge branch 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-06-20 10:56:46 -07:00
head_8xx.S powerpc: Remove second definition of STACK_FRAME_OVERHEAD 2010-11-29 15:48:23 +11:00
head_32.S powerpc/smp: soft-replugged CPUs must go back to start_secondary 2011-04-01 15:37:09 +11:00
head_40x.S Fix common misspellings 2011-03-31 11:26:23 -03:00
head_44x.S Fix common misspellings 2011-03-31 11:26:23 -03:00
head_64.S powerpc: Use MSR_64BIT in places 2011-04-27 14:18:44 +10:00
head_booke.h powerpc/booke: Add Stack Marking support to Booke Exception Prolog 2010-05-05 08:01:52 -04:00
head_fsl_booke.S Fix common misspellings 2011-03-31 11:26:23 -03:00
hw_breakpoint.c powerpc, hw_breakpoint: Tell generic code we have no instruction breakpoints 2010-06-30 13:54:58 +10:00
ibmebus.c PM / Hibernate: Introduce CONFIG_HIBERNATE_CALLBACKS 2011-04-11 22:54:42 +02:00
idle_6xx.S
idle_book3e.S powerpc/book3e: Add generic 64-bit idle powersave support 2010-07-14 14:13:18 +10:00
idle_e500.S
idle_power4.S powerpc/pmac/smp: Properly NAP offlined CPU on G5 2011-04-01 15:37:25 +11:00
idle_power7.S powerpc: Add NAP mode support on Power7 in HV mode 2011-04-20 11:03:24 +10:00
idle.c powerpc: Re-enable preemption before cpu_die() 2010-08-24 15:26:29 +10:00
init_task.c Use new __init_task_data macro in arch init_task.c files. 2009-09-21 06:27:08 +02:00
io-workarounds.c powerpc/pci: Properly initialize IO workaround "private" 2011-04-27 14:18:33 +10:00
io.c powerpc: tiny memcpy_(to|from)io optimisation 2009-11-04 16:43:12 -07:00
iomap.c
iommu.c powerpc: iommu: Add device name to iommu error printks 2010-12-09 15:35:32 +11:00
irq.c powerpc/irq: Stop exporting irq_map 2011-05-04 15:02:15 +10:00
isa-bridge.c
kgdb.c kgdb,ppc: Fix regression in evr register handling 2010-11-17 13:54:58 -06:00
kprobes.c powerpc/kprobes: Remove resume_execution() in kprobes 2010-06-02 17:50:37 +10:00
kvm_emul.S KVM: PPC: Make PV mtmsrd L=1 work with r30 and r31 2010-10-24 10:52:14 +02:00
kvm.c PPC: KVM: Book E doesn't have __end_interrupts. 2010-11-05 14:42:27 -02:00
l2cr_6xx.S Fix common misspellings 2011-03-31 11:26:23 -03:00
legacy_serial.c powerpc: Check device status before adding serial device 2011-04-12 06:29:21 -05:00
lparcfg.c powerpc/pseries: Add page coalescing support 2011-05-04 16:02:21 +10:00
machine_kexec_32.c powerpc/kexec: make masking/disabling interrupts generic 2010-10-14 00:52:46 -05:00
machine_kexec_64.c powerpc/kexec: Fix orphaned offline CPUs across kexec 2010-07-31 15:05:22 +10:00
machine_kexec.c powerpc: Convert to new irq_* function names 2011-03-29 14:48:12 +02:00
Makefile powerpc: Remove unused config in the Makefile 2011-05-19 14:30:40 +10:00
misc_32.S powerpc: Remove second definition of STACK_FRAME_OVERHEAD 2010-11-29 15:48:23 +11:00
misc_64.S powerpc: Remove second definition of STACK_FRAME_OVERHEAD 2010-11-29 15:48:23 +11:00
misc.S powerpc: Remove unneeded cpu_setup/restore from POWER7 cputable entry 2010-11-29 15:48:22 +11:00
module_32.c
module_64.c powerpc: Unify opcode definitions and support 2009-02-23 10:48:56 +11:00
module.c powerpc: remove unused variable 2010-10-05 17:27:54 -07:00
mpc7450-pmu.c perf, arch: Cleanup perf-pmu init vs lockup-detector 2010-11-26 15:14:56 +01:00
msi.c powerpc/PCI: include pci.h in powerpc MSI implementation 2009-03-25 08:54:29 -07:00
nvram_64.c powerpc/nvram: Generalize code for OS partitions in NVRAM 2011-03-04 18:19:04 +11:00
of_platform.c dt/powerpc: Eliminate users of of_platform_{,un}register_driver 2011-02-28 01:36:39 -07:00
paca.c powerpc: In HV mode, use HSPRG0 for PACA 2011-04-20 11:03:22 +10:00
pci_32.c powerpc/pci: Make both ppc32 and ppc64 use sysdata for pci_controller 2011-02-04 11:46:51 -07:00
pci_64.c powerpc/pci: Make both ppc32 and ppc64 use sysdata for pci_controller 2011-02-04 11:46:51 -07:00
pci_dn.c powerpc/pci: Fix crash in PCI code on ppc64 when matching device nodes 2011-03-21 10:57:57 +11:00
pci_of_scan.c powerpc/pci: Make both ppc32 and ppc64 use sysdata for pci_controller 2011-02-04 11:46:51 -07:00
pci-common.c powerpc: Convert to new irq_* function names 2011-03-29 14:48:12 +02:00
perf_callchain.c perf: Factorize callchain context handling 2010-08-19 01:32:11 +02:00
perf_event_fsl_emb.c powerpc, perf: Fix frequency calculation for overflowing counters (FSL version) 2011-01-19 20:05:42 +01:00
perf_event.c powerpc/perf_event: Skip updating kernel counters if register value shrinks 2011-04-18 13:08:23 +10:00
pmc.c powerpc: Convert pmc_owner_lock to raw_spinlock 2010-02-19 14:52:33 +11:00
power4-pmu.c perf, arch: Cleanup perf-pmu init vs lockup-detector 2010-11-26 15:14:56 +01:00
power5-pmu.c perf, arch: Cleanup perf-pmu init vs lockup-detector 2010-11-26 15:14:56 +01:00
power5+-pmu.c perf, arch: Cleanup perf-pmu init vs lockup-detector 2010-11-26 15:14:56 +01:00
power6-pmu.c perf, arch: Cleanup perf-pmu init vs lockup-detector 2010-11-26 15:14:56 +01:00
power7-pmu.c perf, arch: Cleanup perf-pmu init vs lockup-detector 2010-11-26 15:14:56 +01:00
ppc32.h
ppc970-pmu.c perf, arch: Cleanup perf-pmu init vs lockup-detector 2010-11-26 15:14:56 +01:00
ppc_ksyms.c powerpc: Simplify 4k/64k copy_page logic 2011-05-19 14:30:42 +10:00
ppc_save_regs.S Fix common misspellings 2011-03-31 11:26:23 -03:00
proc_powerpc.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
process.c powerpc: Free up some CPU feature bits by moving out MMU-related features 2011-04-27 14:18:52 +10:00
prom_init_check.sh powerpc: Fix compile errors in prom_init_check for gcc 4.5 2010-07-08 18:11:39 +10:00
prom_init.c powerpc/pseries: Add page coalescing support 2011-05-04 16:02:21 +10:00
prom_parse.c of/pci: move of_irq_map_pci() into generic code 2011-02-04 11:46:50 -07:00
prom.c powerpc: Free up some CPU feature bits by moving out MMU-related features 2011-04-27 14:18:52 +10:00
ptrace32.c powerpc: Update compat_arch_ptrace 2010-12-09 15:35:32 +11:00
ptrace.c Fix common misspellings 2011-03-31 11:26:23 -03:00
reloc_64.S
rtas_flash.c powerpc/rtas_flash: Use simple_read_from_buffer 2011-01-21 14:08:34 +11:00
rtas_pci.c powerpc/pci: Clean up direct access to sysdata by RTAS 2009-05-21 15:44:23 +10:00
rtas-proc.c powerpc: Move /proc/ppc64 to /proc/powerpc update 2010-01-15 13:26:17 +11:00
rtas-rtc.c
rtas.c powerpc/pseries: Add page coalescing support 2011-05-04 16:02:21 +10:00
rtasd.c Fix common misspellings 2011-03-31 11:26:23 -03:00
setup_32.c powerpc: Properly handshake CPUs going out of boot spin loop 2011-04-20 11:03:24 +10:00
setup_64.c powerpc: Rename slb0_limit() to safe_stack_limit() and add Book3E support 2011-05-06 13:32:24 +10:00
setup-common.c powerpc: Convert old cpumask API into new one 2011-05-04 15:22:59 +10:00
setup.h
signal_32.c powerpc: fix double syscall restarts 2010-09-22 09:33:50 -07:00
signal_64.c powerpc: Use MSR_64BIT in places 2011-04-27 14:18:44 +10:00
signal.c powerpc: fix double syscall restarts 2010-09-22 09:33:50 -07:00
signal.h powerpc: Sanitize stack pointer in signal handling code 2009-03-27 16:58:24 +11:00
smp-tbsync.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
smp.c powerpc: Convert old cpumask API into new one 2011-05-04 15:22:59 +10:00
softemu8xx.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
stacktrace.c
suspend.c update email address 2010-07-19 10:56:54 +02:00
swsusp_32.S Fix common misspellings 2011-03-31 11:26:23 -03:00
swsusp_64.c
swsusp_asm64.S
swsusp_booke.S powerpc/fsl-booke: Add hibernation support for FSL BookE processors 2010-05-21 07:41:53 -05:00
swsusp.c powerpc/mm: Split mmu_context handling 2008-12-21 14:21:15 +11:00
sys_ppc32.c BKL: remove extraneous #include <smp_lock.h> 2010-11-17 08:59:32 -08:00
syscalls.c Add generic sys_olduname() 2010-03-12 15:52:32 -08:00
sysfs.c powerpc: Per process DSCR + some fixes (try#4) 2011-04-27 14:18:19 +10:00
systbl_chk.c
systbl_chk.sh
systbl.S
tau_6xx.c tree-wide: fix assorted typos all over the place 2009-12-04 15:39:55 +01:00
time.c powerpc: Fix oops if scan_dispatch_log is called too early 2011-04-18 13:08:19 +10:00
traps.c powerpc: Convert old cpumask API into new one 2011-05-04 15:22:59 +10:00
udbg_16550.c powerpc: Add early debug for WSP platforms 2011-05-06 13:32:41 +10:00
udbg.c powerpc: Add early debug for WSP platforms 2011-05-06 13:32:41 +10:00
vdso.c mm: arch: rename in_gate_area_no_task to in_gate_area_no_mm 2011-03-23 16:36:55 -04:00
vecemu.c
vector.S powerpc: Remove static branch hint in giveup_altivec 2011-05-19 14:30:42 +10:00
vio.c powerpc/iommu: Use coherent_dma_mask for alloc_coherent 2010-12-09 15:17:50 +11:00
vmlinux.lds.S percpu: align percpu readmostly subsection to cacheline 2011-01-25 14:26:50 +01:00