* [kvm-unit-tests PATCH] x86: add HPET counter read micro benchmark and enable/disable torture tests
@ 2025-07-02 14:51 Igor Mammedov
2025-07-04 15:51 ` Igor Mammedov
0 siblings, 1 reply; 2+ messages in thread
From: Igor Mammedov @ 2025-07-02 14:51 UTC (permalink / raw)
To: kvm; +Cc: pbonzini
test is to be used for benchmarking/validating HPET main counter read
how to run:
QEMU=/foo/qemu-system-x86_64 x86/run x86/hpet_read_test.flat -smp X
where X is max number of logical CPUs on host
it will 1st execute concurrent read benchmark
and after that it will run torture test enabling/disabling HPET counter,
while running readers in parallel. Goal is to verify counter that always
goes up.
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
---
this also will be used for testing upcomming HPET fain-grained
locking QEMU series
---
x86/Makefile.common | 2 ++
x86/hpet_read_test.c | 66 ++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 68 insertions(+)
create mode 100644 x86/hpet_read_test.c
diff --git a/x86/Makefile.common b/x86/Makefile.common
index 5663a65d..ef0e09a6 100644
--- a/x86/Makefile.common
+++ b/x86/Makefile.common
@@ -101,6 +101,8 @@ tests-common += $(TEST_DIR)/realmode.$(exe) \
realmode_bits := $(if $(call cc-option,-m16,""),16,32)
endif
+tests-common += $(TEST_DIR)/hpet_read_test.$(exe)
+
test_cases: $(tests-common) $(tests)
$(TEST_DIR)/%.o: CFLAGS += -std=gnu99 -ffreestanding -I $(SRCDIR)/lib -I $(SRCDIR)/lib/x86 -I lib
diff --git a/x86/hpet_read_test.c b/x86/hpet_read_test.c
new file mode 100644
index 00000000..2f56ab6b
--- /dev/null
+++ b/x86/hpet_read_test.c
@@ -0,0 +1,66 @@
+#include "libcflat.h"
+#include "smp.h"
+
+#define HPET_ADDR 0xFED00000L
+#define HPET_COUNTER_ADDR ((uint8_t *)HPET_ADDR + 0xF0UL)
+#define HPET_CONFIG_ADDR ((uint8_t *)HPET_ADDR + 0x10UL)
+#define HPET_ENABLE_BIT 0x01UL
+#define HPET_CLK_PERIOD 10
+
+static int fail = 0;
+static void hpet_reader(void *data)
+{
+ long cycles = (long)data;
+
+ while (cycles--) {
+ uint64_t old_counter = 0, new_counter;
+ new_counter = *(volatile uint64_t *)HPET_COUNTER_ADDR;
+ if (new_counter < old_counter) {
+ fail = 1;
+ report_abort("HPET counter jumped back");
+ }
+ }
+}
+
+
+static void hpet_writer(void *data)
+{
+ int i;
+ long cycles = (long)data;
+
+ for (i = 0; i < cycles; ++i)
+ if (i % 2)
+ *(volatile uint64_t *)HPET_CONFIG_ADDR |= HPET_ENABLE_BIT;
+ else
+ *(volatile uint64_t *)HPET_CONFIG_ADDR &= ~HPET_ENABLE_BIT;
+}
+
+int main(void)
+{
+ long cycles = 100000;
+ int i;
+ int ncpus;
+ uint64_t start, end, time_ns;
+
+ ncpus = cpu_count();
+ do {
+ printf("starting concurrent read bench on %d cpus\n", ncpus);
+ *(volatile uint64_t *)HPET_CONFIG_ADDR |= HPET_ENABLE_BIT;
+ start = *(volatile uint64_t *)HPET_COUNTER_ADDR;
+ on_cpus(hpet_reader, (void *)cycles);
+ end = (*(volatile uint64_t *)HPET_COUNTER_ADDR);
+ time_ns = (end - start) * HPET_CLK_PERIOD;
+ report(time_ns, "read test took %lu ms\n", time_ns/1000000);
+ } while (0);
+
+ do {
+ printf("starting enable/disable with concurent readers torture\n");
+ for (i = 2; i < ncpus; i++)
+ on_cpu_async(i, hpet_reader, (void *)cycles);
+
+ on_cpu(1, hpet_writer, (void *)cycles);
+ } while (0);
+
+ report(!fail, "passed torture test\n");
+ return report_summary();
+}
--
2.47.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [kvm-unit-tests PATCH] x86: add HPET counter read micro benchmark and enable/disable torture tests
2025-07-02 14:51 [kvm-unit-tests PATCH] x86: add HPET counter read micro benchmark and enable/disable torture tests Igor Mammedov
@ 2025-07-04 15:51 ` Igor Mammedov
0 siblings, 0 replies; 2+ messages in thread
From: Igor Mammedov @ 2025-07-04 15:51 UTC (permalink / raw)
To: kvm; +Cc: pbonzini
On Wed, 2 Jul 2025 16:51:23 +0200
Igor Mammedov <imammedo@redhat.com> wrote:
> test is to be used for benchmarking/validating HPET main counter read
>
> how to run:
> QEMU=/foo/qemu-system-x86_64 x86/run x86/hpet_read_test.flat -smp X
> where X is max number of logical CPUs on host
>
> it will 1st execute concurrent read benchmark
> and after that it will run torture test enabling/disabling HPET counter,
> while running readers in parallel. Goal is to verify counter that always
> goes up.
ignore that, fail check in torture test is broken.
I'll send fixed v2 later on
>
> Signed-off-by: Igor Mammedov <imammedo@redhat.com>
> ---
> this also will be used for testing upcomming HPET fain-grained
> locking QEMU series
>
> ---
> x86/Makefile.common | 2 ++
> x86/hpet_read_test.c | 66 ++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 68 insertions(+)
> create mode 100644 x86/hpet_read_test.c
>
> diff --git a/x86/Makefile.common b/x86/Makefile.common
> index 5663a65d..ef0e09a6 100644
> --- a/x86/Makefile.common
> +++ b/x86/Makefile.common
> @@ -101,6 +101,8 @@ tests-common += $(TEST_DIR)/realmode.$(exe) \
> realmode_bits := $(if $(call cc-option,-m16,""),16,32)
> endif
>
> +tests-common += $(TEST_DIR)/hpet_read_test.$(exe)
> +
> test_cases: $(tests-common) $(tests)
>
> $(TEST_DIR)/%.o: CFLAGS += -std=gnu99 -ffreestanding -I $(SRCDIR)/lib -I $(SRCDIR)/lib/x86 -I lib
> diff --git a/x86/hpet_read_test.c b/x86/hpet_read_test.c
> new file mode 100644
> index 00000000..2f56ab6b
> --- /dev/null
> +++ b/x86/hpet_read_test.c
> @@ -0,0 +1,66 @@
> +#include "libcflat.h"
> +#include "smp.h"
> +
> +#define HPET_ADDR 0xFED00000L
> +#define HPET_COUNTER_ADDR ((uint8_t *)HPET_ADDR + 0xF0UL)
> +#define HPET_CONFIG_ADDR ((uint8_t *)HPET_ADDR + 0x10UL)
> +#define HPET_ENABLE_BIT 0x01UL
> +#define HPET_CLK_PERIOD 10
> +
> +static int fail = 0;
> +static void hpet_reader(void *data)
> +{
> + long cycles = (long)data;
> +
> + while (cycles--) {
> + uint64_t old_counter = 0, new_counter;
> + new_counter = *(volatile uint64_t *)HPET_COUNTER_ADDR;
> + if (new_counter < old_counter) {
> + fail = 1;
> + report_abort("HPET counter jumped back");
> + }
> + }
> +}
> +
> +
> +static void hpet_writer(void *data)
> +{
> + int i;
> + long cycles = (long)data;
> +
> + for (i = 0; i < cycles; ++i)
> + if (i % 2)
> + *(volatile uint64_t *)HPET_CONFIG_ADDR |= HPET_ENABLE_BIT;
> + else
> + *(volatile uint64_t *)HPET_CONFIG_ADDR &= ~HPET_ENABLE_BIT;
> +}
> +
> +int main(void)
> +{
> + long cycles = 100000;
> + int i;
> + int ncpus;
> + uint64_t start, end, time_ns;
> +
> + ncpus = cpu_count();
> + do {
> + printf("starting concurrent read bench on %d cpus\n", ncpus);
> + *(volatile uint64_t *)HPET_CONFIG_ADDR |= HPET_ENABLE_BIT;
> + start = *(volatile uint64_t *)HPET_COUNTER_ADDR;
> + on_cpus(hpet_reader, (void *)cycles);
> + end = (*(volatile uint64_t *)HPET_COUNTER_ADDR);
> + time_ns = (end - start) * HPET_CLK_PERIOD;
> + report(time_ns, "read test took %lu ms\n", time_ns/1000000);
> + } while (0);
> +
> + do {
> + printf("starting enable/disable with concurent readers torture\n");
> + for (i = 2; i < ncpus; i++)
> + on_cpu_async(i, hpet_reader, (void *)cycles);
> +
> + on_cpu(1, hpet_writer, (void *)cycles);
> + } while (0);
> +
> + report(!fail, "passed torture test\n");
> + return report_summary();
> +}
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