Re: [patch 6/8] 2.6.22-rc3 perfmon2 : IBS implementation for AMD64

David Rientjes
2007-06-15T20:19:15Z

On Fri, 15 Jun 2007, Robert Richter wrote:

> Index: linux-2.6.22-rc3/arch/i386/perfmon/perfmon.c
> ===================================================================
> --- linux-2.6.22-rc3.orig/arch/i386/perfmon/perfmon.c
> +++ linux-2.6.22-rc3/arch/i386/perfmon/perfmon.c
> @@ -5,6 +5,9 @@
> * Copyright (c) 2005-2006 Hewlett-Packard Development Company, L.P.
> * Contributed by Stephane Eranian <eranian@hpl.hp.com>
> *
> + * Copyright (c) 2007 Advanced Micro Devices, Inc.
> + * Contributed by Robert Richter <robert.richter@amd.com>
> + *
> * This program is free software; you can redistribute it and/or
> * modify it under the terms of version 2 of the GNU General Public
> * License as published by the Free Software Foundation.
> @@ -66,6 +69,49 @@ static inline int get_smt_id(void)
> #endif
> }
>
> +static inline u64 __pfm_pmd_sread(unsigned int vpmd)
> +{
> + struct pfm_arch_pmu_info *arch_info = pfm_pmu_conf->arch_info;
> + return arch_info->vpmds[get_smt_id()][vpmd];
> +}
> +
> +static inline void __pfm_pmd_swrite(unsigned int vpmd, u64 val)
> +{
> + struct pfm_arch_pmu_info *arch_info = pfm_pmu_conf->arch_info;
> + arch_info->vpmds[get_smt_id()][vpmd] = val;
> +}
> +
> +/* Context must be locked for atomic read and write operations */
> +
> +u64 pfm_pmd_sread(struct pfm_context *ctx, unsigned int cnum)
> +{
> + unsigned int vpmd = pfm_pmu_conf->pmd_desc[cnum].hw_addr;
> + BUG_ON(! spin_is_locked(&ctx->lock));
> + if (vpmd >= PFM_NUM_VPMDS)
> + return 0;
> + return __pfm_pmd_sread(vpmd);
> +}

If you're going to do error checking here even though you're already
checking for vpmd >= PFM_NUM_VPMDS in pfm_pmd_sinc(), then please return
an errno such as -EINVAL instead of 0 here. Otherwise a distinct caller
can still set pfm_pmu_conf->arch_info->vpmds[get_smt_id()][vpmd] to 1 if
it calls pfm_pmd_sread() outside of pfm_pmd_sinc().

> +void pfm_pmd_swrite(struct pfm_context *ctx, unsigned int cnum, u64 val)
> +{
> + unsigned int vpmd = pfm_pmu_conf->pmd_desc[cnum].hw_addr;
> + BUG_ON(! spin_is_locked(&ctx->lock));
> + if (vpmd >= PFM_NUM_VPMDS)
> + return;
> + __pfm_pmd_swrite(vpmd, val);
> +}
> +
> +static void pfm_pmd_sinc(struct pfm_context *ctx, unsigned int cnum)
> +{
> + unsigned int vpmd = pfm_pmu_conf->pmd_desc[cnum].hw_addr;
> + u64 val = 0;
> + BUG_ON(! spin_is_locked(&ctx->lock));
> + if (vpmd >= PFM_NUM_VPMDS)
> + return;
> + val = __pfm_pmd_sread(vpmd);
> + __pfm_pmd_swrite(vpmd, val + 1);
> +}
> +
> void __pfm_write_reg_p4(const struct pfm_arch_ext_reg *xreg, u64 val)
> {
> u64 pmi;
> @@ -309,7 +355,13 @@ static int pfm_stop_save_p6(struct pfm_c
> count = set->nused_pmds;
> for (i = 0; count; i++) {
> if (test_bit(i, ulp(set->used_pmds))) {
> - val = pfm_arch_read_pmd(ctx, i);
> + count--;
> + /* Skip for IBS event counter */
> + if (unlikely(i == arch_info->ibsfetchctr_idx))
> + continue;
> + if (unlikely(i == arch_info->ibsopctr_idx))
> + continue;
> + val = pfm_read_pmd(ctx, i);
> if (likely(test_bit(i, ulp(cnt_mask)))) {
> if (!(val & wmask)) {
> __set_bit(i, ulp(set->povfl_pmds));

Why are you moving the count-- ahead in this code block? Isn't it more
appropriate in the for() statement alongside i++ anyway? (There's
multiple instances of this in this patch.)

> @@ -318,7 +370,6 @@ static int pfm_stop_save_p6(struct pfm_c
> val = (pmds[i] & ~ovfl_mask) | (val & ovfl_mask);
> }
> pmds[i] = val;
> - count--;
> }
> }
> /* 0 means: no need to save PMDs at upper level */
> @@ -328,6 +379,55 @@ static int pfm_stop_save_p6(struct pfm_c
> static int pfm_stop_save_amd64(struct pfm_context *ctx,
> struct pfm_event_set *set)
> {

Does this need ctx->lock to be locked even in the !(arch_info->flags &
PFM_X86_FL_IBS) case? If so, it needs a comment.

> + struct pfm_arch_pmu_info *arch_info = pfm_pmu_conf->arch_info;
> + struct pfm_reg_desc *pmc_desc = pfm_pmu_conf->pmc_desc;
> + u64 val = 0;
> +
> + if (arch_info->flags & PFM_X86_FL_IBS) {
> + /* Check for IBS events */
> + BUG_ON(!spin_is_locked(&ctx->lock));
> + do {
> + if (unlikely(test_bit(arch_info->ibsfetchctr_idx,
> + ulp(set->povfl_pmds)))) {
> + PFM_DBG("Warning: IBS fetch data already pending");
> + continue;
> + }
> + rdmsrl(pmc_desc[arch_info->ibsfetchctl_idx].hw_addr,
> + val);
> + if (!(val & PFM_AMD64_IBSFETCHVAL))
> + continue;
> + PFM_DBG_ovfl("New IBS fetch data available");
> + __set_bit(arch_info->ibsfetchctr_idx,
> + ulp(set->povfl_pmds));
> + set->npend_ovfls++;
> + /* Increment event counter */
> + pfm_pmd_sinc(ctx, arch_info->ibsfetchctr_idx);
> + /* Update PMD */
> + set->view->set_pmds[arch_info->ibsfetchctr_idx] =
> + pfm_read_pmd(ctx, arch_info->ibsfetchctr_idx);
> + } while (0);

Please move this out of the do { ... } while (0); loop and change the
continue's to goto's.

> + do {
> + if (unlikely(test_bit(arch_info->ibsopctr_idx,
> + ulp(set->povfl_pmds)))) {
> + PFM_DBG("Warning: IBS execution data already pending");
> + continue;
> + }
> + rdmsrl(pmc_desc[arch_info->ibsopctl_idx].hw_addr, val);
> + if (!(val & PFM_AMD64_IBSOPVAL))
> + continue;
> + PFM_DBG_ovfl("New IBS execution data available");
> + __set_bit(arch_info->ibsopctr_idx,
> + ulp(set->povfl_pmds));
> + set->npend_ovfls++;
> + /* Increment event counter */
> + pfm_pmd_sinc(ctx, arch_info->ibsopctr_idx);
> + /* Update PMD */
> + set->view->set_pmds[arch_info->ibsopctr_idx] =
> + pfm_read_pmd(ctx, arch_info->ibsopctr_idx);
> + } while (0);

Likewise.

> @@ -637,6 +737,7 @@ void pfm_arch_start(struct task_struct *
> struct pfm_event_set *set)
> {
> struct pfm_arch_context *ctx_arch;
> + struct pfm_reg_desc* pmc_desc;
> u64 *mask;
> u16 i, num;
>

Kernel coding style is struct pfm_reg_desc *pmc_desc here.

> @@ -673,11 +774,18 @@ void pfm_arch_start(struct task_struct *
> */
> num = pfm_pmu_conf->num_pmcs;
> mask = pfm_pmu_conf->impl_pmcs;
> + pmc_desc = pfm_pmu_conf->pmc_desc;
> for (i = 0; num; i++) {
> - if (test_bit(i, ulp(mask))) {
> + if (!test_bit(i, ulp(mask)))
> + continue;
> + num--;
> + if (!test_bit(i, ulp(set->used_pmcs)))
> + /* If the PMC is not used, we initialize with
> + * interrupts disabled. */
> + pfm_arch_write_pmc(ctx, i, set->pmcs[i]
> + & ~pmc_desc[i].no_emul64_msk);
> + else
> pfm_arch_write_pmc(ctx, i, set->pmcs[i]);
> - num--;
> - }
> }

num-- should be placed alongside i++ in the for() statement.

> @@ -839,18 +947,37 @@ static int __kprobes pfm_has_ovfl_p6(voi
> xrd = arch_info->pmd_addrs;
>
> for (i = 0; num; i++) {
> - if (test_bit(i, ulp(cnt_mask))) {
> - rdmsrl(xrd[i].addrs[0], val);
> - if (!(val & wmask))
> - return 1;
> - num--;
> - }
> + if (!test_bit(i, ulp(cnt_mask)))
> + continue;
> + num--;
> + /* Skip for IBS event counter */
> + if (unlikely(i == arch_info->ibsfetchctr_idx))
> + continue;
> + if (unlikely(i == arch_info->ibsopctr_idx))
> + continue;
> + rdmsrl(xrd[i].addrs[0], val);
> + if (!(val & wmask))
> + return 1;
> }

Same as above.

> @@ -973,11 +1100,18 @@ static struct notifier_block pfm_nmi_nb=
> int pfm_arch_pmu_config_init(struct _pfm_pmu_config *cfg)
> {
> struct pfm_arch_pmu_info *arch_info = cfg->arch_info;
> - struct pfm_arch_ext_reg *pc;
> + struct pfm_arch_ext_reg *pc, *pd;
> u64 *mask;
> unsigned int i, num, ena;
> + unsigned int ibs_check = 0;
> +#define IBS_CHECK_FETCHCTL 0x01
> +#define IBS_CHECK_FETCHCTR 0x02
> +#define IBS_CHECK_OPCTL 0x04
> +#define IBS_CHECK_OPCTR 0x08
> +#define IBS_CHECK_ALL 0x0f
>

These cannot occur in the middle of a function. Please move them to an
appropriate header file.

> pc = arch_info->pmc_addrs;
> + pd = arch_info->pmd_addrs;
>
> /*
> * ensure that PMU description is able to deal with NMI watchdog using
> @@ -1023,18 +1157,86 @@ int pfm_arch_pmu_config_init(struct _pfm
> num = cfg->num_pmcs;
> mask = cfg->impl_pmcs;
> ena = 0;
> + ibs_check = 0;

Didn't you initialize this to 0?

> Index: linux-2.6.22-rc3/arch/x86_64/perfmon/perfmon_k8.c
> ===================================================================
> --- linux-2.6.22-rc3.orig/arch/x86_64/perfmon/perfmon_k8.c
> +++ linux-2.6.22-rc3/arch/x86_64/perfmon/perfmon_k8.c
> @@ -5,6 +5,9 @@
> * Copyright (c) 2005-2006 Hewlett-Packard Development Company, L.P.
> * Contributed by Stephane Eranian <eranian@hpl.hp.com>
> *
> + * Copyright (c) 2007 Advanced Micro Devices, Inc.
> + * Contributed by Robert Richter <robert.richter@amd.com>
> + *
> * This program is free software; you can redistribute it and/or
> * modify it under the terms of version 2 of the GNU General Public
> * License as published by the Free Software Foundation.
> @@ -25,6 +28,7 @@
> #include <asm/nmi.h>
>
> MODULE_AUTHOR("Stephane Eranian <eranian@hpl.hp.com>");
> +MODULE_AUTHOR("Robert Richter <robert.richter@amd.com>");
> MODULE_DESCRIPTION("AMD64 PMU description table");
> MODULE_LICENSE("GPL");
>
> @@ -38,12 +42,26 @@ static struct pfm_arch_pmu_info pfm_k8_p
> /* pmc1 */ {{MSR_K7_EVNTSEL1, 0}, 1, PFM_REGT_EN},
> /* pmc2 */ {{MSR_K7_EVNTSEL2, 0}, 2, PFM_REGT_EN},
> /* pmc3 */ {{MSR_K7_EVNTSEL3, 0}, 3, PFM_REGT_EN},
> +/* pmc4 */ {{MSR_AMD64_IBSFETCHCTL, 0}, 0, PFM_REGT_EN|PFM_REGT_IBS},
> +/* pmc5 */ {{MSR_AMD64_IBSOPCTL, 0}, 0, PFM_REGT_EN|PFM_REGT_IBS},
> },
> .pmd_addrs = {
> /* pmd0 */ {{MSR_K7_PERFCTR0, 0}, 0, PFM_REGT_CTR},
> /* pmd1 */ {{MSR_K7_PERFCTR1, 0}, 0, PFM_REGT_CTR},
> /* pmd2 */ {{MSR_K7_PERFCTR2, 0}, 0, PFM_REGT_CTR},
> /* pmd3 */ {{MSR_K7_PERFCTR3, 0}, 0, PFM_REGT_CTR},
> +/* pmd4 */ {{0, 0}, 0, PFM_REGT_CTR|PFM_REGT_IBS},
> +/* pmd5 */ {{MSR_AMD64_IBSFETCHCTL, 0}, 0, PFM_REGT_IBS},
> +/* pmd6 */ {{MSR_AMD64_IBSFETCHLINAD, 0}, 0, PFM_REGT_IBS},
> +/* pmd7 */ {{MSR_AMD64_IBSFETCHPHYSAD, 0}, 0, PFM_REGT_IBS},
> +/* pmd8 */ {{0, 0}, 0, PFM_REGT_CTR|PFM_REGT_IBS},
> +/* pmd9 */ {{MSR_AMD64_IBSOPCTL, 0}, 0, PFM_REGT_IBS},
> +/* pmd10 */ {{MSR_AMD64_IBSOPRIP, 0}, 0, PFM_REGT_IBS},
> +/* pmd11 */ {{MSR_AMD64_IBSOPDATA, 0}, 0, PFM_REGT_IBS},
> +/* pmd12 */ {{MSR_AMD64_IBSOPDATA2, 0}, 0, PFM_REGT_IBS},
> +/* pmd13 */ {{MSR_AMD64_IBSOPDATA3, 0}, 0, PFM_REGT_IBS|PFM_REGT_IBS_EXT},
> +/* pmd14 */ {{MSR_AMD64_IBSDCLINAD, 0}, 0, PFM_REGT_IBS|PFM_REGT_IBS_EXT},
> +/* pmd15 */ {{MSR_AMD64_IBSDCPHYSAD, 0}, 0, PFM_REGT_IBS|PFM_REGT_IBS_EXT},
> },
> .pmu_style = PFM_X86_PMU_AMD64
> };
> @@ -65,11 +83,26 @@ static struct pfm_arch_pmu_info pfm_k8_p
> | (1ULL<<20) \
> | (1ULL<<21))
>
> +/*
> + * We mark readonly bits as reserved and use the PMC for control
> + * operations only. Interrupt enable and clear bits are reserved too.
> + * IBSFETCHCTL is also implemented as PMD, where data can be read
> + * from. Same applies to IBSOPCTR.
> + */
> +#define PFM_AMD64_IBSFETCHCTL_VAL PFM_AMD64_IBSFETCHEN
> +#define PFM_AMD64_IBSFETCHCTL_NO64 PFM_AMD64_IBSFETCHEN
> +#define PFM_AMD64_IBSFETCHCTL_RSVD (~((1ULL<<16)-1))
> +#define PFM_AMD64_IBSOPCTL_VAL PFM_AMD64_IBSOPEN
> +#define PFM_AMD64_IBSOPCTL_NO64 PFM_AMD64_IBSOPEN
> +#define PFM_AMD64_IBSOPCTL_RSVD (~((1ULL<<16)-1))
> +
> static struct pfm_reg_desc pfm_k8_pmc_desc[]={
> /* pmc0 */ PMC_D(PFM_REG_I64, "PERFSEL0", PFM_K8_VAL, PFM_K8_RSVD, PFM_K8_NO64, MSR_K7_EVNTSEL0),
> /* pmc1 */ PMC_D(PFM_REG_I64, "PERFSEL1", PFM_K8_VAL, PFM_K8_RSVD, PFM_K8_NO64, MSR_K7_EVNTSEL1),
> /* pmc2 */ PMC_D(PFM_REG_I64, "PERFSEL2", PFM_K8_VAL, PFM_K8_RSVD, PFM_K8_NO64, MSR_K7_EVNTSEL2),
> /* pmc3 */ PMC_D(PFM_REG_I64, "PERFSEL3", PFM_K8_VAL, PFM_K8_RSVD, PFM_K8_NO64, MSR_K7_EVNTSEL3),
> +/* pmc4 */ PMC_D(PFM_REG_I, "IBSFETCHCTL", PFM_AMD64_IBSFETCHCTL_VAL, PFM_AMD64_IBSFETCHCTL_RSVD, PFM_AMD64_IBSFETCHCTL_NO64, MSR_AMD64_IBSFETCHCTL),
> +/* pmc5 */ PMC_D(PFM_REG_I, "IBSOPCTL", PFM_AMD64_IBSOPCTL_VAL, PFM_AMD64_IBSOPCTL_RSVD, PFM_AMD64_IBSOPCTL_NO64, MSR_AMD64_IBSOPCTL),
> };
> #define PFM_AMD_NUM_PMCS ARRAY_SIZE(pfm_k8_pmc_desc)
>
> @@ -78,6 +111,18 @@ static struct pfm_reg_desc pfm_k8_pmd_de
> /* pmd1 */ PMD_D(PFM_REG_C, "PERFCTR1", MSR_K7_PERFCTR1),
> /* pmd2 */ PMD_D(PFM_REG_C, "PERFCTR2", MSR_K7_PERFCTR2),
> /* pmd3 */ PMD_D(PFM_REG_C, "PERFCTR3", MSR_K7_PERFCTR3),
> +/* pmd4 */ PMD_D(PFM_REG_ICV, "IBSFETCHCTR", PFM_VPMD_AMD64_IBSFETCHCTR),
> +/* pmd5 */ PMD_D(PFM_REG_IRO, "IBSFETCHCTL", MSR_AMD64_IBSFETCHCTL),
> +/* pmd6 */ PMD_D(PFM_REG_IRO, "IBSFETCHLINAD", MSR_AMD64_IBSFETCHLINAD),
> +/* pmd7 */ PMD_D(PFM_REG_IRO, "IBSFETCHPHYSAD", MSR_AMD64_IBSFETCHPHYSAD),
> +/* pmd8 */ PMD_D(PFM_REG_ICV, "IBSOPCTR", PFM_VPMD_AMD64_IBSOPCTR),
> +/* pmd9 */ PMD_D(PFM_REG_IRO, "IBSOPCTL", MSR_AMD64_IBSOPCTL),
> +/* pmd10 */ PMD_D(PFM_REG_IRO, "IBSOPRIP", MSR_AMD64_IBSOPRIP),
> +/* pmd11 */ PMD_D(PFM_REG_IRO, "IBSOPDATA", MSR_AMD64_IBSOPDATA),
> +/* pmd12 */ PMD_D(PFM_REG_IRO, "IBSOPDATA2", MSR_AMD64_IBSOPDATA2),
> +/* pmd13 */ PMD_D(PFM_REG_IRO, "IBSOPDATA3", MSR_AMD64_IBSOPDATA3),
> +/* pmd14 */ PMD_D(PFM_REG_IRO, "IBSDCLINAD", MSR_AMD64_IBSDCLINAD),
> +/* pmd15 */ PMD_D(PFM_REG_IRO, "IBSDCPHYSAD", MSR_AMD64_IBSDCPHYSAD),
> };
> #define PFM_AMD_NUM_PMDS ARRAY_SIZE(pfm_k8_pmd_desc)
>
> @@ -284,6 +329,9 @@ static int pfm_k8_detect_nmi(void)
> * auto-detect which perfctr/eventsel is used by NMI watchdog
> */
> for (i=0; i < PFM_AMD_NUM_PMDS; i++) {
> + /* skip IBS registers */
> + if (pfm_k8_pmu_info.pmc_addrs[i].reg_type & PFM_REGT_IBS)
> + continue;
> if (avail_to_resrv_perfctr_nmi(pfm_k8_pmd_desc[i].hw_addr))
> continue;
>
> @@ -332,10 +380,75 @@ static int pfm_k8_probe_pmu(void)
> pfm_k8_setup_nb_event_control();
>
> PFM_INFO("Using AMD64 PMU");
> + if (pfm_k8_pmu_info.flags & PFM_X86_FL_IBS)
> + PFM_INFO("IBS is supported by processor");
> + if (pfm_k8_pmu_info.flags & PFM_X86_FL_IBS_EXT)
> + PFM_INFO("IBS extended registers are supported by processor");
>
> return 0;
> }
>
> +static inline void
> +pfm_amd64_check_register(struct pfm_pmu_config *cfg,
> + struct pfm_reg_desc *reg,
> + struct pfm_arch_ext_reg *ext_reg)
> +{
> + struct pfm_arch_pmu_info *arch_info = cfg->arch_info;
> +
> + if (!(ext_reg->reg_type & PFM_REGT_AMD64))
> + /* No special AMD64 PMU register */
> + return;
> +
> + /* Disable register */
> + reg->type &= ~PFM_REG_I;
> +
> + switch (ext_reg->reg_type & PFM_REGT_AMD64) {
> + case (PFM_REGT_IBS):
> + /* IBS register */
> + if (!(arch_info->flags & PFM_X86_FL_IBS))
> + return;
> + break;
> + case (PFM_REGT_IBS|PFM_REGT_IBS_EXT):
> + /* IBS extended register */
> + if (!(arch_info->flags & PFM_X86_FL_IBS_EXT))
> + return;
> + break;
> + default:
> + return;
> + }
> +
> + /* Enable register */
> + reg->type |= PFM_REG_I;
> +}
> +
> +static void pfm_amd64_setup_pmu(struct pfm_pmu_config *cfg)
> +{
> + u16 i;
> + struct pfm_arch_pmu_info *arch_info = cfg->arch_info;
> +
> + /* set PMU features depending on CPUID */
> + arch_info->flags &= ~(PFM_X86_FL_IBS|PFM_X86_FL_IBS_EXT);
> + switch (current_cpu_data.x86) {
> + case 15:
> + break;
> + case 16:
> + arch_info->flags |= PFM_X86_FL_IBS;
> + break;
> + default:
> + break;
> + }

Could you just collapse this into

if (current_cpu_data.x86 == 16)
arch_info->flags |= PFM_X86_FL_IBS;