On 29/10/2020 17:16, Jan Kiszka wrote:
> On 29.10.20 15:55, Ralf Ramsauer wrote:
>> On x86_64 systems, this test inmate measures the time that is required to
>> read
>> a value from main memory. Via rdtsc, it measures the CPU cycles that are
>> required for the access. Access can either happen cached, or uncached. In
>> case
>> of uncached access, the cache line will be flushed before access.
>>
>> This tool repeats the measurement for 10e6 times, and outputs the
>> average cycles that were required for the access. Before accessing the
>> actual measurement, a dummy test is used to determine the average
>> overhead of one single measurement.
>>
>> And that's pretty useful, because this tool gives a lot of insights of
>> differences between the root and the non-root cell: With tiny effort, we
>> can also run it on Linux.
>>
>> If the 'overhead' time differs between root and non-root cell, this can
>> be an indicator that there might be some timing or speed differences
>> between the root and non-root cell.
>>
>> If the 'uncached' or 'cached' average time differs between the non-root
>> and root cell, it's an indicator that both might have different hardware
>> configurations / setups.
>>
>> Signed-off-by: Ralf Ramsauer <[email protected]>
>> ---
>> since v2:
>> - Move host code to tools/demos :-)
>>
>> since v1:
>> - Move host code to tools/
>>
>> since RFC:
>> - move the inmate to demos instead of tests
>>
>>
>> .gitignore | 1 +
>> inmates/demos/x86/Makefile | 4 +++-
>> tools/Makefile | 9 +++++++--
>> tools/demos/cache-timings.c | 29 +++++++++++++++++++++++++++++
>> 4 files changed, 40 insertions(+), 3 deletions(-)
>> create mode 100644 tools/demos/cache-timings.c
>>
>> diff --git a/.gitignore b/.gitignore
>> index 1d8905ab..245733cb 100644
>> --- a/.gitignore
>> +++ b/.gitignore
>> @@ -21,6 +21,7 @@ hypervisor/hypervisor.lds
>> inmates/lib/arm/inmate.lds
>> inmates/lib/arm64/inmate.lds
>> pyjailhouse/pci_defs.py
>> +tools/demos/cache-timings
>> tools/demos/ivshmem-demo
>> tools/jailhouse
>> tools/jailhouse-gcov-extract
>> diff --git a/inmates/demos/x86/Makefile b/inmates/demos/x86/Makefile
>> index f53b739e..47b79869 100644
>> --- a/inmates/demos/x86/Makefile
>> +++ b/inmates/demos/x86/Makefile
>> @@ -13,7 +13,8 @@
>> include $(INMATES_LIB)/Makefile.lib
>>
>> INMATES := tiny-demo.bin apic-demo.bin ioapic-demo.bin 32-bit-demo.bin \
>> - pci-demo.bin e1000-demo.bin ivshmem-demo.bin smp-demo.bin
>> + pci-demo.bin e1000-demo.bin ivshmem-demo.bin smp-demo.bin \
>> + cache-timings.bin
>>
>> tiny-demo-y := tiny-demo.o
>> apic-demo-y := apic-demo.o
>> @@ -22,6 +23,7 @@ pci-demo-y := pci-demo.o
>> e1000-demo-y := e1000-demo.o
>> ivshmem-demo-y := ../ivshmem-demo.o
>> smp-demo-y := smp-demo.o
>> +cache-timings-y := cache-timings.o
>>
>> $(eval $(call DECLARE_32_BIT,32-bit-demo))
>> 32-bit-demo-y := 32-bit-demo.o
>> diff --git a/tools/Makefile b/tools/Makefile
>> index 8cf5df84..62585369 100644
>> --- a/tools/Makefile
>> +++ b/tools/Makefile
>> @@ -35,6 +35,13 @@ KBUILD_CFLAGS += $(call cc-option, -fno-pie)
>> KBUILD_CFLAGS += $(call cc-option, -no-pie)
>>
>> BINARIES := jailhouse demos/ivshmem-demo
>> +targets += jailhouse.o demos/ivshmem-demo.o
>> +
>> +ifeq ($(ARCH),x86)
>> +BINARIES += demos/cache-timings
>> +targets += demos/cache-timings.o
>> +endif # $(ARCH),x86
>> +
>> always-y := $(BINARIES)
>>
>> HAS_PYTHON_MAKO := \
>> @@ -104,8 +111,6 @@ define cmd_gen_man
>> sed 's/$${VERSION}/$(shell cat $(src)/../VERSION)/g' $< > $@
>> endef
>>
>> -targets += jailhouse.o demos/ivshmem-demo.o
>> -
>> $(obj)/%: $(obj)/%.o
>> $(call if_changed,ld)
>>
>> diff --git a/tools/demos/cache-timings.c b/tools/demos/cache-timings.c
>> new file mode 100644
>> index 00000000..2c591dab
>> --- /dev/null
>> +++ b/tools/demos/cache-timings.c
>> @@ -0,0 +1,29 @@
>> +/*
>> + * Jailhouse, a Linux-based partitioning hypervisor
>> + *
>> + * Copyright (c) OTH Regensburg, 2020
>> + *
>> + * Authors:
>> + * Ralf Ramsauer <[email protected]>
>> + *
>> + * This work is licensed under the terms of the GNU GPL, version 2. See
>> + * the COPYING file in the top-level directory.
>> + */
>> +
>> +#include <stdbool.h>
>> +#include <stdio.h>
>> +
>> +#define printk printf
>> +
>> +typedef unsigned int u32;
>> +typedef unsigned long long u64;
>> +
>> +void inmate_main(void);
>> +
>> +#include "../inmates/demos/x86/cache-timings-common.c"
>> +
>> +int main(void)
>> +{
>> + inmate_main();
>> + return 0;
>> +}
>>
>
> Look mom, I shrunk my patch! But I guess that was not intional...
My dearest son, please have a closer look at path one.
Rhymed-By: Ralf Ramsauer <[email protected]>
>
> Patch 1 is already in next, so you only need to refresh this one.
>
> Jan
>
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