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* [PATCH 01/19] powerpc: Don't disable kernel FP/VMX/VSX MSR bits on context switch
@ 2015-10-28  0:50 Anton Blanchard
  2015-10-28  0:50 ` [PATCH 02/19] powerpc: Don't disable MSR bits in do_load_up_transact_*() functions Anton Blanchard
                   ` (17 more replies)
  0 siblings, 18 replies; 23+ messages in thread
From: Anton Blanchard @ 2015-10-28  0:50 UTC (permalink / raw)
  To: benh, paulus, mpe, mikey, cyrilbur; +Cc: linuxppc-dev

Writing the MSR is slow, so we want to avoid it whenever possible.

A subsequent patch will add a debug option that strictly manages the
FP/VMX/VSX unavailable bits. For now just remove it, matching what
we do in other areas of the kernel (eg enable_kernel_altivec()).

A context switch microbenchmark using yield():

http://ozlabs.org/~anton/junkcode/context_switch2.c

./context_switch2 --test=yield --fp 0 0

shows an improvement of almost 3% on POWER8.

Signed-off-by: Anton Blanchard <anton@samba.org>
---
 arch/powerpc/kernel/entry_64.S | 15 +--------------
 1 file changed, 1 insertion(+), 14 deletions(-)

diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index a94f155..93bb284 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -453,26 +453,13 @@ _GLOBAL(_switch)
 	SAVE_8GPRS(14, r1)
 	SAVE_10GPRS(22, r1)
 	mflr	r20		/* Return to switch caller */
-	mfmsr	r22
-	li	r0, MSR_FP
-#ifdef CONFIG_VSX
-BEGIN_FTR_SECTION
-	oris	r0,r0,MSR_VSX@h	/* Disable VSX */
-END_FTR_SECTION_IFSET(CPU_FTR_VSX)
-#endif /* CONFIG_VSX */
 #ifdef CONFIG_ALTIVEC
 BEGIN_FTR_SECTION
-	oris	r0,r0,MSR_VEC@h	/* Disable altivec */
 	mfspr	r24,SPRN_VRSAVE	/* save vrsave register value */
 	std	r24,THREAD_VRSAVE(r3)
 END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
 #endif /* CONFIG_ALTIVEC */
-	and.	r0,r0,r22
-	beq+	1f
-	andc	r22,r22,r0
-	MTMSRD(r22)
-	isync
-1:	std	r20,_NIP(r1)
+	std	r20,_NIP(r1)
 	mfcr	r23
 	std	r23,_CCR(r1)
 	std	r1,KSP(r3)	/* Set old stack pointer */
-- 
2.5.0

^ permalink raw reply related	[flat|nested] 23+ messages in thread
* [PATCH 00/19] Context switch improvements
@ 2015-10-29  0:43 Anton Blanchard
  2015-10-29  0:43 ` [PATCH 04/19] powerpc: Remove redundant mflr in _switch Anton Blanchard
  0 siblings, 1 reply; 23+ messages in thread
From: Anton Blanchard @ 2015-10-29  0:43 UTC (permalink / raw)
  To: benh, paulus, mpe, mikey, cyrilbur, scottwood; +Cc: linuxppc-dev

Here are various improvements to our context switch path. Some of the
highlights:

- Group all mfsprs and mtsprs in __switch_to(), which gives us a
  10% improvement on POWER8.

- Create giveup_all() and flush_all_to_thread() so we only write the
  MSR once, which gives us a 3% improvement on POWER8.

- Create disable_kernel_{fp,altivec,vsx,spe}() and add a debug boot
  option (ppc_strict_facility_enable) to minimise kernel code running
  with floating point and vector bits enabled.

- Make giveup_vsx() and flush_vsx_to_thread() handle FP and Altivec
  state, so they behave more like their sister functions.

Scott: There are changes to the SPE code here which I have only been
able to compile test.

Anton
--

Anton Blanchard (19):
  powerpc: Don't disable kernel FP/VMX/VSX MSR bits on context switch
  powerpc: Don't disable MSR bits in do_load_up_transact_*() functions
  powerpc: Create context switch helpers save_sprs() and restore_sprs()
  powerpc: Remove redundant mflr in _switch
  powerpc: Remove UP only lazy floating point and vector optimisations
  powerpc: Simplify TM restore checks
  powerpc: Create mtmsrd_isync()
  powerpc: Remove NULL task struct pointer checks in FP and vector code
  powerpc: Move part of giveup_fpu,altivec,spe into c
  powerpc: Move part of giveup_vsx into c
  crypto: vmx: Only call enable_kernel_vsx()
  powerpc: Create msr_check_and_{set,clear}()
  powerpc: Create disable_kernel_{fp,altivec,vsx,spe}()
  powerpc: Add ppc_strict_facility_enable boot option
  powerpc: Remove fp_enable() and vec_enable(), use
    msr_check_and_{set,clear}()
  powerpc: create giveup_all()
  powerpc: create flush_all_to_thread()
  powerpc: Rearrange __switch_to()
  powerpc: clean up asm/switch_to.h

 Documentation/kernel-parameters.txt      |   6 +
 arch/powerpc/crypto/aes-spe-glue.c       |   1 +
 arch/powerpc/crypto/sha1-spe-glue.c      |   1 +
 arch/powerpc/crypto/sha256-spe-glue.c    |   1 +
 arch/powerpc/include/asm/processor.h     |   9 +-
 arch/powerpc/include/asm/reg.h           |  17 ++
 arch/powerpc/include/asm/switch_to.h     |  65 ++---
 arch/powerpc/kernel/align.c              |   2 +
 arch/powerpc/kernel/entry_64.S           |  75 +----
 arch/powerpc/kernel/fpu.S                |  73 +----
 arch/powerpc/kernel/head_fsl_booke.S     |  42 +--
 arch/powerpc/kernel/idle_power7.S        |   7 -
 arch/powerpc/kernel/ppc_ksyms.c          |   6 -
 arch/powerpc/kernel/process.c            | 471 ++++++++++++++++++-------------
 arch/powerpc/kernel/signal_32.c          |  22 +-
 arch/powerpc/kernel/signal_64.c          |  22 +-
 arch/powerpc/kernel/swsusp.c             |   4 +-
 arch/powerpc/kernel/vector.S             | 112 +-------
 arch/powerpc/kvm/book3s_hv.c             |   5 +-
 arch/powerpc/kvm/book3s_paired_singles.c |   1 +
 arch/powerpc/kvm/book3s_pr.c             |  21 +-
 arch/powerpc/kvm/booke.c                 |   4 +
 arch/powerpc/lib/vmx-helper.c            |   2 +
 arch/powerpc/lib/xor_vmx.c               |   4 +
 drivers/crypto/vmx/aes.c                 |   6 +-
 drivers/crypto/vmx/aes_cbc.c             |   6 +-
 drivers/crypto/vmx/aes_ctr.c             |   6 +-
 drivers/crypto/vmx/ghash.c               |  12 +-
 lib/raid6/altivec.uc                     |   1 +
 29 files changed, 376 insertions(+), 628 deletions(-)

-- 
2.5.0

^ permalink raw reply	[flat|nested] 23+ messages in thread
end of thread, other threads:[~2015-10-29  0:45 UTC | newest]

Thread overview: 23+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2015-10-28  0:50 [PATCH 01/19] powerpc: Don't disable kernel FP/VMX/VSX MSR bits on context switch Anton Blanchard
2015-10-28  0:50 ` [PATCH 02/19] powerpc: Don't disable MSR bits in do_load_up_transact_*() functions Anton Blanchard
2015-10-28  0:50 ` [PATCH 03/19] powerpc: Create context switch helpers save_sprs() and restore_sprs() Anton Blanchard
2015-10-28  0:50 ` [PATCH 04/19] powerpc: Remove redundant mflr in _switch Anton Blanchard
2015-10-28  0:50 ` [PATCH 05/19] powerpc: Remove UP only lazy floating point and vector optimisations Anton Blanchard
2015-10-28  0:50 ` [PATCH 06/19] powerpc: Simplify TM restore checks Anton Blanchard
2015-10-28  0:50 ` [PATCH 07/19] powerpc: Create mtmsrd_isync() Anton Blanchard
2015-10-28  0:50 ` [PATCH 08/19] powerpc: Remove NULL task struct pointer checks in FP and vector code Anton Blanchard
2015-10-28  0:50 ` [PATCH 09/19] powerpc: Move part of giveup_fpu,altivec,spe into c Anton Blanchard
2015-10-28  3:17   ` [PATCH 09/19] powerpc: Move part of giveup_fpu, altivec, spe " kbuild test robot
2015-10-28  0:50 ` [PATCH 10/19] powerpc: Move part of giveup_vsx " Anton Blanchard
2015-10-28  0:50 ` [PATCH 11/19] crypto: vmx: Only call enable_kernel_vsx() Anton Blanchard
2015-10-28  0:51 ` [PATCH 12/19] powerpc: Create msr_check_and_{set,clear}() Anton Blanchard
2015-10-28  0:51 ` [PATCH 13/19] powerpc: Create disable_kernel_{fp,altivec,vsx,spe}() Anton Blanchard
2015-10-28  0:51 ` [PATCH 14/19] powerpc: Add ppc_strict_facility_enable boot option Anton Blanchard
2015-10-28  0:51 ` [PATCH 15/19] powerpc: Remove fp_enable() and vec_enable(), use msr_check_and_{set, clear}() Anton Blanchard
2015-10-28  0:51 ` [PATCH 16/19] powerpc: create giveup_all() Anton Blanchard
2015-10-28  0:51 ` [PATCH 17/19] powerpc: create flush_all_to_thread() Anton Blanchard
2015-10-28  0:51 ` [PATCH 18/19] powerpc: Rearrange __switch_to() Anton Blanchard
2015-10-28  0:51 ` [PATCH 19/19] powerpc: clean up asm/switch_to.h Anton Blanchard
2015-10-28  3:19   ` kbuild test robot
2015-10-28  4:24   ` kbuild test robot
  -- strict thread matches above, loose matches on Subject: below --
2015-10-29  0:43 [PATCH 00/19] Context switch improvements Anton Blanchard
2015-10-29  0:43 ` [PATCH 04/19] powerpc: Remove redundant mflr in _switch Anton Blanchard

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