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Re: [kvm-unit-tests PATCH v2 5/9] arm: pmu: Basic event counter Tests
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From: |
Auger Eric |
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Subject: |
Re: [kvm-unit-tests PATCH v2 5/9] arm: pmu: Basic event counter Tests |
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Date: |
Thu, 12 Mar 2020 12:19:18 +0100 |
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User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 |
Hi Drew,
On 3/5/20 10:33 AM, Andrew Jones wrote:
> On Thu, Jan 30, 2020 at 12:25:06PM +0100, Eric Auger wrote:
>> Adds the following tests:
>> - event-counter-config: test event counter configuration
>> - basic-event-count:
>> - programs counters #0 and #1 to count 2 required events
>> (resp. CPU_CYCLES and INST_RETIRED). Counter #0 is preset
>> to a value close enough to the 32b
>> overflow limit so that we check the overflow bit is set
>> after the execution of the asm loop.
>> - mem-access: counts MEM_ACCESS event on counters #0 and #1
>> with and without 32-bit overflow.
>>
>> Signed-off-by: Eric Auger <address@hidden>
>>
>> ---
>>
>> v1 -> v2:
>> - fix PMCNTENSET_EL0 and PMCNTENCLR_EL0 op0
>> - print PMEVTYPER SH
>> - properly clobber used regs and add "cc"
>> - simplify mem_access_loop
>> ---
>> arm/pmu.c | 269 ++++++++++++++++++++++++++++++++++++++++++++++
>> arm/unittests.cfg | 18 ++++
>> 2 files changed, 287 insertions(+)
>>
>> diff --git a/arm/pmu.c b/arm/pmu.c
>> index 4a26a76..1b0101f 100644
>> --- a/arm/pmu.c
>> +++ b/arm/pmu.c
>> @@ -18,9 +18,15 @@
>> #include "asm/barrier.h"
>> #include "asm/sysreg.h"
>> #include "asm/processor.h"
>> +#include <bitops.h>
>> +#include <asm/gic.h>
>>
>> #define PMU_PMCR_E (1 << 0)
>> +#define PMU_PMCR_P (1 << 1)
>> #define PMU_PMCR_C (1 << 2)
>> +#define PMU_PMCR_D (1 << 3)
>> +#define PMU_PMCR_X (1 << 4)
>> +#define PMU_PMCR_DP (1 << 5)
>> #define PMU_PMCR_LC (1 << 6)
>> #define PMU_PMCR_N_SHIFT 11
>> #define PMU_PMCR_N_MASK 0x1f
>> @@ -104,6 +110,9 @@ static inline void precise_instrs_loop(int loop,
>> uint32_t pmcr)
>>
>> /* event counter tests only implemented for aarch64 */
>> static void test_event_introspection(void) {}
>> +static void test_event_counter_config(void) {}
>> +static void test_basic_event_count(void) {}
>> +static void test_mem_access(void) {}
>>
>> #elif defined(__aarch64__)
>> #define ID_AA64DFR0_PERFMON_SHIFT 8
>> @@ -145,6 +154,33 @@ static inline void precise_instrs_loop(int loop,
>> uint32_t pmcr)
>> }
>>
>> #define PMCEID1_EL0 sys_reg(3, 3, 9, 12, 7)
>> +#define PMCNTENSET_EL0 sys_reg(3, 3, 9, 12, 1)
>> +#define PMCNTENCLR_EL0 sys_reg(3, 3, 9, 12, 2)
>> +
>> +#define PMEVTYPER_EXCLUDE_EL1 (1 << 31)
>> +#define PMEVTYPER_EXCLUDE_EL0 (1 << 30)
>> +
>> +#define regn_el0(__reg, __n) __reg ## __n ## _el0
>> +#define write_regn(__reg, __n, __val) \
>> + write_sysreg((__val), __reg ## __n ## _el0)
>> +
>> +#define read_regn(__reg, __n) \
>> + read_sysreg(__reg ## __n ## _el0)
>
> You can delete regn_el0() since you don't use it anyway.
>
> The el0 should probably be in the macro names,
>
> write_regn_el0()
> read_regn_el0()
>
> Also they could go in lib/arm64/asm/sysreg.h
>
>> +
>> +#define print_pmevtyper(__s, __n) do { \
>> + uint32_t val; \
>> + val = read_regn(pmevtyper, __n);\
>> + report_info("%s pmevtyper%d=0x%x, eventcount=0x%x (p=%ld, u=%ld
>> nsk=%ld, nsu=%ld, nsh=%ld m=%ld, mt=%ld, sh=%ld)", \
>> + (__s), (__n), val, val & 0xFFFF, \
>> + (BIT_MASK(31) & val) >> 31, \
>> + (BIT_MASK(30) & val) >> 30, \
>> + (BIT_MASK(29) & val) >> 29, \
>> + (BIT_MASK(28) & val) >> 28, \
>> + (BIT_MASK(27) & val) >> 27, \
>> + (BIT_MASK(26) & val) >> 26, \
>> + (BIT_MASK(25) & val) >> 25); \
>> + (BIT_MASK(24) & val) >> 24); \
>> + } while (0)
>>
>> static bool is_event_supported(uint32_t n, bool warn)
>> {
>> @@ -198,6 +234,230 @@ static void test_event_introspection(void)
>> report(required_events, "Check required events are implemented");
>> }
>>
>> +/*
>> + * Extra instructions inserted by the compiler would be difficult to
>> compensate
>> + * for, so hand assemble everything between, and including, the PMCR
>> accesses
>> + * to start and stop counting. isb instructions are inserted to make sure
>> + * pmccntr read after this function returns the exact instructions executed
>> + * in the controlled block. Loads @loop times the data at @address into x9.
>> + */
>> +static void mem_access_loop(void *addr, int loop, uint32_t pmcr)
>> +{
>> +asm volatile(
>> + " msr pmcr_el0, %[pmcr]\n"
>> + " isb\n"
>> + " mov x10, %[loop]\n"
>> + "1: sub x10, x10, #1\n"
>> + " ldr x9, [%[addr]]\n"
>
> indent is wrong for line above
>
>> + " cmp x10, #0x0\n"
>> + " b.gt 1b\n"
>> + " msr pmcr_el0, xzr\n"
>> + " isb\n"
>> + :
>> + : [addr] "r" (addr), [pmcr] "r" (pmcr), [loop] "r" (loop)
>> + : "x9", "x10", "cc");
>> +}
>> +
>> +static void pmu_reset(void)
>> +{
>> + /* reset all counters, counting disabled at PMCR level*/
>> + set_pmcr(pmu.pmcr_ro | PMU_PMCR_LC | PMU_PMCR_C | PMU_PMCR_P);
>> + /* Disable all counters */
>> + write_sysreg_s(0xFFFFFFFF, PMCNTENCLR_EL0);
>> + /* clear overflow reg */
>> + write_sysreg(0xFFFFFFFF, pmovsclr_el0);
>> + /* disable overflow interrupts on all counters */
>> + write_sysreg(0xFFFFFFFF, pmintenclr_el1);
>> + isb();
>> +}
>> +
>> +static void test_event_counter_config(void)
>> +{
>> + int i;
>> +
>> + if (!pmu.nb_implemented_counters) {
>> + report_skip("No event counter, skip ...");
>> + return;
>> + }
>> +
>> + pmu_reset();
>> +
>> + /*
>> + * Test setting through PMESELR/PMXEVTYPER and PMEVTYPERn read,
>> + * select counter 0
>> + */
>> + write_sysreg(1, PMSELR_EL0);
>> + /* program this counter to count unsupported event */
>> + write_sysreg(0xEA, PMXEVTYPER_EL0);
>> + write_sysreg(0xdeadbeef, PMXEVCNTR_EL0);
>> + report((read_regn(pmevtyper, 1) & 0xFFF) == 0xEA,
>> + "PMESELR/PMXEVTYPER/PMEVTYPERn");
>> + report((read_regn(pmevcntr, 1) == 0xdeadbeef),
>> + "PMESELR/PMXEVCNTR/PMEVCNTRn");
>> +
>> + /* try to configure an unsupported event within the range [0x0, 0x3F] */
>> + for (i = 0; i <= 0x3F; i++) {
>> + if (!is_event_supported(i, false))
>> + break;
>> + }
>> + if (i > 0x3F) {
>> + report_skip("pmevtyper: all events within [0x0, 0x3F] are
>> supported");
>> + return;
>> + }
>> +
>> + /* select counter 0 */
>> + write_sysreg(0, PMSELR_EL0);
>> + /* program this counter to count unsupported event */
>> + write_sysreg(i, PMXEVCNTR_EL0);
>> + /* read the counter value */
>> + read_sysreg(PMXEVCNTR_EL0);
>> + report(read_sysreg(PMXEVCNTR_EL0) == i,
>> + "read of a counter programmed with unsupported event");
>> +
>> +}
>> +
>> +static bool satisfy_prerequisites(uint32_t *events, unsigned int nb_events)
>> +{
>> + int i;
>> +
>> + if (pmu.nb_implemented_counters < nb_events) {
>> + report_skip("Skip test as number of counters is too small (%d)",
>> + pmu.nb_implemented_counters);
>> + return false;
>> + }
>> +
>> + for (i = 0; i < nb_events; i++) {
>> + if (!is_event_supported(events[i], false)) {
>> + report_skip("Skip test as event %d is not supported",
>> + events[i]);
>> + return false;
>> + }
>> + }
>> + return true;
>> +}
>> +
>> +static void test_basic_event_count(void)
>> +{
>> + uint32_t implemented_counter_mask, non_implemented_counter_mask;
>> + uint32_t counter_mask;
>> + uint32_t events[] = {
>> + 0x11, /* CPU_CYCLES */
>> + 0x8, /* INST_RETIRED */
>> + };
>
> #define CPU_CYCLES 0x11
> #define INST_RETIRED 0x8
>
> then no need for the comments and ...
>
>> +
>> + if (!satisfy_prerequisites(events, ARRAY_SIZE(events)))
>> + return;
>> +
>> + implemented_counter_mask = BIT(pmu.nb_implemented_counters) - 1;
>> + non_implemented_counter_mask = ~(BIT(31) | implemented_counter_mask);
>> + counter_mask = implemented_counter_mask | non_implemented_counter_mask;
>> +
>> + write_regn(pmevtyper, 0, events[0] | PMEVTYPER_EXCLUDE_EL0);
>> + write_regn(pmevtyper, 1, events[1] | PMEVTYPER_EXCLUDE_EL0);
>
> ... here we can see what we're doing more clearing using the defines
> instead of array members.
>
>> +
>> + /* disable all counters */
>> + write_sysreg_s(0xFFFFFFFF, PMCNTENCLR_EL0);
>> + report(!read_sysreg_s(PMCNTENCLR_EL0) && !read_sysreg_s(PMCNTENSET_EL0),
>> + "pmcntenclr: disable all counters");
>> +
>> + /*
>> + * clear cycle and all event counters and allow counter enablement
>> + * through PMCNTENSET. LC is RES1.
>> + */
>> + set_pmcr(pmu.pmcr_ro | PMU_PMCR_LC | PMU_PMCR_C | PMU_PMCR_P);
>> + isb();
>> + report(get_pmcr() == (pmu.pmcr_ro | PMU_PMCR_LC), "pmcr: reset
>> counters");
>> +
>> + /* Preset counter #0 to 0xFFFFFFF0 to trigger an overflow interrupt */
>> + write_regn(pmevcntr, 0, 0xFFFFFFF0);
>> + report(read_regn(pmevcntr, 0) == 0xFFFFFFF0,
>> + "counter #0 preset to 0xFFFFFFF0");
>> + report(!read_regn(pmevcntr, 1), "counter #1 is 0");
>> +
>> + /*
>> + * Enable all implemented counters and also attempt to enable
>> + * not supported counters. Counting still is disabled by !PMCR.E
>> + */
>> + write_sysreg_s(counter_mask, PMCNTENSET_EL0);
>> +
>> + /* check only those implemented are enabled */
>> + report((read_sysreg_s(PMCNTENSET_EL0) == read_sysreg_s(PMCNTENCLR_EL0))
>> &&
>> + (read_sysreg_s(PMCNTENSET_EL0) == implemented_counter_mask),
>> + "pmcntenset: enabled implemented_counters");
>> +
>> + /* Disable all counters but counters #0 and #1 */
>> + write_sysreg_s(~0x3, PMCNTENCLR_EL0);
>
> First time you've used ~ to define a mask. I prefer this to all the
> 0xFFF..'s, but I prefer consistency and defines even more.
>
>> + report((read_sysreg_s(PMCNTENSET_EL0) == read_sysreg_s(PMCNTENCLR_EL0))
>> &&
>> + (read_sysreg_s(PMCNTENSET_EL0) == 0x3),
>> + "pmcntenset: just enabled #0 and #1");
>> +
>> + /* clear overflow register */
>> + write_sysreg(0xFFFFFFFF, pmovsclr_el0);
>> + report(!read_sysreg(pmovsclr_el0), "check overflow reg is 0");
>> +
>> + /* disable overflow interrupts on all counters*/
>> + write_sysreg(0xFFFFFFFF, pmintenclr_el1);
>> + report(!read_sysreg(pmintenclr_el1),
>> + "pmintenclr_el1=0, all interrupts disabled");
>> +
>> + /* enable overflow interrupts on all event counters */
>> + write_sysreg(implemented_counter_mask | non_implemented_counter_mask,
>> + pmintenset_el1);
>> + report(read_sysreg(pmintenset_el1) == implemented_counter_mask,
>> + "overflow interrupts enabled on all implemented counters");
>> +
>> + /* Set PMCR.E, execute asm code and unset PMCR.E */
>> + precise_instrs_loop(20, pmu.pmcr_ro | PMU_PMCR_E);
>> +
>> + report_info("counter #0 is 0x%lx (CPU_CYCLES)",
>> + read_regn(pmevcntr, 0));
>> + report_info("counter #1 is 0x%lx (INST_RETIRED)",
>> + read_regn(pmevcntr, 1));
>> +
>> + report_info("overflow reg = 0x%lx", read_sysreg(pmovsclr_el0));
>> + report(read_sysreg(pmovsclr_el0) & 0x1,
>> + "check overflow happened on #0 only");
>> +}
>> +
>> +static void test_mem_access(void)
>> +{
>> + void *addr = malloc(PAGE_SIZE);
>> + uint32_t events[] = {
>> + 0x13, /* MEM_ACCESS */
>> + 0x13, /* MEM_ACCESS */
>> + };
>
> #define MEM_ACCESS 0x13
>
>> +
>> + if (!satisfy_prerequisites(events, ARRAY_SIZE(events)))
>
> No need to check the same event twice. Just call satisfy_prerequisites
> with ((uint32_t []){ MEM_ACCESS }, 1)
satisfy_prerequisites also test the number of implemented counters match
the ARRAY_SIZE.
In Practice most of my tests use 2 counters. I could skip the tests if
we don't have 2 counters.
But well ...
Eric
>
>> + return;
>> +
>> + pmu_reset();
>> +
>> + write_regn(pmevtyper, 0, events[0] | PMEVTYPER_EXCLUDE_EL0);
>> + write_regn(pmevtyper, 1, events[1] | PMEVTYPER_EXCLUDE_EL0);
>
> Same comment on using defines rather than array members.
>
>> + write_sysreg_s(0x3, PMCNTENSET_EL0);
>> + isb();
>> + mem_access_loop(addr, 20, pmu.pmcr_ro | PMU_PMCR_E);
>> + report_info("counter #0 is %ld (MEM_ACCESS)", read_regn(pmevcntr, 0));
>> + report_info("counter #1 is %ld (MEM_ACCESS)", read_regn(pmevcntr, 1));
>> + /* We may measure more than 20 mem access depending on the core */
>> + report((read_regn(pmevcntr, 0) == read_regn(pmevcntr, 1)) &&
>> + (read_regn(pmevcntr, 0) >= 20) && !read_sysreg(pmovsclr_el0),
>> + "Ran 20 mem accesses");
>> +
>> + pmu_reset();
>> +
>> + write_regn(pmevcntr, 0, 0xFFFFFFFA);
>> + write_regn(pmevcntr, 1, 0xFFFFFFF0);
>> + write_sysreg_s(0x3, PMCNTENSET_EL0);
>> + isb();
>> + mem_access_loop(addr, 20, pmu.pmcr_ro | PMU_PMCR_E);
>> + report(read_sysreg(pmovsclr_el0) == 0x3,
>> + "Ran 20 mem accesses with expected overflows on both counters");
>> + report_info("cnt#0 = %ld cnt#1=%ld overflow=0x%lx",
>> + read_regn(pmevcntr, 0), read_regn(pmevcntr, 1),
>> + read_sysreg(pmovsclr_el0));
>> +}
>> +
>> #endif
>>
>> /*
>> @@ -388,6 +648,15 @@ int main(int argc, char *argv[])
>> } else if (strcmp(argv[1], "event-introspection") == 0) {
>> report_prefix_push(argv[1]);
>> test_event_introspection();
>> + } else if (strcmp(argv[1], "event-counter-config") == 0) {
>> + report_prefix_push(argv[1]);
>> + test_event_counter_config();
>> + } else if (strcmp(argv[1], "basic-event-count") == 0) {
>> + report_prefix_push(argv[1]);
>> + test_basic_event_count();
>> + } else if (strcmp(argv[1], "mem-access") == 0) {
>> + report_prefix_push(argv[1]);
>> + test_mem_access();
>
> missing the pops. I know they're not necessary since we finish the tests
> afterwards, but the universe must stay balanced. Where there's a yin, we
> should put a yang.
>
>> } else {
>> report_abort("Unknown sub-test '%s'", argv[1]);
>> }
>> diff --git a/arm/unittests.cfg b/arm/unittests.cfg
>> index 4433ef3..7a59403 100644
>> --- a/arm/unittests.cfg
>> +++ b/arm/unittests.cfg
>> @@ -72,6 +72,24 @@ groups = pmu
>> arch = arm64
>> extra_params = -append 'event-introspection'
>>
>> +[pmu-event-counter-config]
>> +file = pmu.flat
>> +groups = pmu
>> +arch = arm64
>> +extra_params = -append 'event-counter-config'
>> +
>> +[pmu-basic-event-count]
>> +file = pmu.flat
>> +groups = pmu
>> +arch = arm64
>> +extra_params = -append 'basic-event-count'
>> +
>> +[pmu-mem-access]
>> +file = pmu.flat
>> +groups = pmu
>> +arch = arm64
>> +extra_params = -append 'mem-access'
>> +
>> # Test PMU support (TCG) with -icount IPC=1
>> #[pmu-tcg-icount-1]
>> #file = pmu.flat
>> --
>> 2.20.1
>>
>>
>
> I only skimmed this looking for style/framework issues. I'd prefer more
> defines in general to all the hex, but I won't insist on that.
>
> Thanks,
> drew
>