From cb2c9b2741346eb23b177187a51ff5abf08295bd Mon Sep 17 00:00:00 2001 From: Anton Blanchard Date: Mon, 13 Feb 2006 14:48:35 +1100 Subject: [PATCH] powerpc: Fix runlatch performance issues The runlatch SPR can take a lot of time to write. My original runlatch code would set it on every exception entry even though most of the time this was not required. It would also continually set it in the idle loop, which is an issue on an SMT capable processor. Now we cache the runlatch value in a threadinfo bit, and only check for it in decrementer and hardware interrupt exceptions as well as the idle loop. Boot on POWER3, POWER5 and iseries, and compile tested on pmac32. Signed-off-by: Anton Blanchard Signed-off-by: Paul Mackerras --- arch/powerpc/kernel/head_64.S | 12 ++---------- arch/powerpc/kernel/process.c | 32 ++++++++++++++++++++++++++++++++ arch/powerpc/platforms/iseries/setup.c | 1 + 3 files changed, 35 insertions(+), 10 deletions(-) (limited to 'arch') diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S index 2b03a09fe5e9..bb845eed0e98 100644 --- a/arch/powerpc/kernel/head_64.S +++ b/arch/powerpc/kernel/head_64.S @@ -319,7 +319,6 @@ exception_marker: label##_pSeries: \ HMT_MEDIUM; \ mtspr SPRN_SPRG1,r13; /* save r13 */ \ - RUNLATCH_ON(r13); \ EXCEPTION_PROLOG_PSERIES(PACA_EXGEN, label##_common) #define STD_EXCEPTION_ISERIES(n, label, area) \ @@ -327,7 +326,6 @@ label##_pSeries: \ label##_iSeries: \ HMT_MEDIUM; \ mtspr SPRN_SPRG1,r13; /* save r13 */ \ - RUNLATCH_ON(r13); \ EXCEPTION_PROLOG_ISERIES_1(area); \ EXCEPTION_PROLOG_ISERIES_2; \ b label##_common @@ -337,7 +335,6 @@ label##_iSeries: \ label##_iSeries: \ HMT_MEDIUM; \ mtspr SPRN_SPRG1,r13; /* save r13 */ \ - RUNLATCH_ON(r13); \ EXCEPTION_PROLOG_ISERIES_1(PACA_EXGEN); \ lbz r10,PACAPROCENABLED(r13); \ cmpwi 0,r10,0; \ @@ -390,6 +387,7 @@ label##_common: \ label##_common: \ EXCEPTION_PROLOG_COMMON(trap, PACA_EXGEN); \ DISABLE_INTS; \ + bl .ppc64_runlatch_on; \ addi r3,r1,STACK_FRAME_OVERHEAD; \ bl hdlr; \ b .ret_from_except_lite @@ -407,7 +405,6 @@ __start_interrupts: _machine_check_pSeries: HMT_MEDIUM mtspr SPRN_SPRG1,r13 /* save r13 */ - RUNLATCH_ON(r13) EXCEPTION_PROLOG_PSERIES(PACA_EXMC, machine_check_common) . = 0x300 @@ -434,7 +431,6 @@ END_FTR_SECTION_IFCLR(CPU_FTR_SLB) data_access_slb_pSeries: HMT_MEDIUM mtspr SPRN_SPRG1,r13 - RUNLATCH_ON(r13) mfspr r13,SPRN_SPRG3 /* get paca address into r13 */ std r3,PACA_EXSLB+EX_R3(r13) mfspr r3,SPRN_DAR @@ -460,7 +456,6 @@ data_access_slb_pSeries: instruction_access_slb_pSeries: HMT_MEDIUM mtspr SPRN_SPRG1,r13 - RUNLATCH_ON(r13) mfspr r13,SPRN_SPRG3 /* get paca address into r13 */ std r3,PACA_EXSLB+EX_R3(r13) mfspr r3,SPRN_SRR0 /* SRR0 is faulting address */ @@ -491,7 +486,6 @@ instruction_access_slb_pSeries: .globl system_call_pSeries system_call_pSeries: HMT_MEDIUM - RUNLATCH_ON(r9) mr r9,r13 mfmsr r10 mfspr r13,SPRN_SPRG3 @@ -575,7 +569,6 @@ slb_miss_user_pseries: system_reset_fwnmi: HMT_MEDIUM mtspr SPRN_SPRG1,r13 /* save r13 */ - RUNLATCH_ON(r13) EXCEPTION_PROLOG_PSERIES(PACA_EXGEN, system_reset_common) .globl machine_check_fwnmi @@ -583,7 +576,6 @@ system_reset_fwnmi: machine_check_fwnmi: HMT_MEDIUM mtspr SPRN_SPRG1,r13 /* save r13 */ - RUNLATCH_ON(r13) EXCEPTION_PROLOG_PSERIES(PACA_EXMC, machine_check_common) #ifdef CONFIG_PPC_ISERIES @@ -894,7 +886,6 @@ unrecov_fer: .align 7 .globl data_access_common data_access_common: - RUNLATCH_ON(r10) /* It wont fit in the 0x300 handler */ mfspr r10,SPRN_DAR std r10,PACA_EXGEN+EX_DAR(r13) mfspr r10,SPRN_DSISR @@ -1042,6 +1033,7 @@ hardware_interrupt_common: EXCEPTION_PROLOG_COMMON(0x500, PACA_EXGEN) hardware_interrupt_entry: DISABLE_INTS + bl .ppc64_runlatch_on addi r3,r1,STACK_FRAME_OVERHEAD bl .do_IRQ b .ret_from_except_lite diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index 57703994a063..c225cf154bfe 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -888,3 +888,35 @@ void dump_stack(void) show_stack(current, NULL); } EXPORT_SYMBOL(dump_stack); + +#ifdef CONFIG_PPC64 +void ppc64_runlatch_on(void) +{ + unsigned long ctrl; + + if (cpu_has_feature(CPU_FTR_CTRL) && !test_thread_flag(TIF_RUNLATCH)) { + HMT_medium(); + + ctrl = mfspr(SPRN_CTRLF); + ctrl |= CTRL_RUNLATCH; + mtspr(SPRN_CTRLT, ctrl); + + set_thread_flag(TIF_RUNLATCH); + } +} + +void ppc64_runlatch_off(void) +{ + unsigned long ctrl; + + if (cpu_has_feature(CPU_FTR_CTRL) && test_thread_flag(TIF_RUNLATCH)) { + HMT_medium(); + + clear_thread_flag(TIF_RUNLATCH); + + ctrl = mfspr(SPRN_CTRLF); + ctrl &= ~CTRL_RUNLATCH; + mtspr(SPRN_CTRLT, ctrl); + } +} +#endif diff --git a/arch/powerpc/platforms/iseries/setup.c b/arch/powerpc/platforms/iseries/setup.c index 3f8790146b00..3ecc4a652d82 100644 --- a/arch/powerpc/platforms/iseries/setup.c +++ b/arch/powerpc/platforms/iseries/setup.c @@ -648,6 +648,7 @@ static void yield_shared_processor(void) * here and let the timer_interrupt code sort out the actual time. */ get_lppaca()->int_dword.fields.decr_int = 1; + ppc64_runlatch_on(); process_iSeries_events(); } -- cgit v1.2.2