Hi Alexandru, On 4/19/23 11:39, Alexandru Elisei wrote: > Hi, > > On Wed, Apr 19, 2023 at 09:32:10AM +0200, Eric Auger wrote: >> Hi, >> >> On 4/12/23 10:47, Mark Rutland wrote: >>> On Tue, Apr 04, 2023 at 02:47:47PM +0200, Andrew Jones wrote: >>>> On Tue, Apr 04, 2023 at 08:23:15AM +0200, Eric Auger wrote: >>>>> Hi, >>>>> >>>>> On 3/15/23 12:07, Eric Auger wrote: >>>>>> On some HW (ThunderXv2), some random failures of >>>>>> pmu-chain-promotion test can be observed. >>>>>> >>>>>> pmu-chain-promotion is composed of several subtests >>>>>> which run 2 mem_access loops. The initial value of >>>>>> the counter is set so that no overflow is expected on >>>>>> the first loop run and overflow is expected on the second. >>>>>> However it is observed that sometimes we get an overflow >>>>>> on the first run. It looks related to some variability of >>>>>> the mem_acess count. This variability is observed on all >>>>>> HW I have access to, with different span though. On >>>>>> ThunderX2 HW it looks the margin that is currently taken >>>>>> is too small and we regularly hit failure. >>>>>> >>>>>> although the first goal of this series is to increase >>>>>> the count/margin used in those tests, it also attempts >>>>>> to improve the pmu-chain-promotion logs, add some barriers >>>>>> in the mem-access loop, clarify the chain counter >>>>>> enable/disable sequence. >>>>>> >>>>>> A new 'pmu-memaccess-reliability' is also introduced to >>>>>> detect issues with MEM_ACCESS event variability and make >>>>>> the debug easier. >>> As a minor nit, 'pmu-mem-access-reliability' would be more consistent with >>> 'pmu-mem-access'. The lack of a dash in 'memaccess' tripped me up while I was >>> trying to run those two tests. >> I can easily respin with that renaming. thanks for the feedback. Waiting >> a little bit more if somebody has any other comment. > Started reviewing the series last week, something came up and I had to stop > after the first patch (very nice improvement, by the way). I will finish > the review by the end of this week. OK no problem. Thanks for your time. Eric > > Thanks, > Alex > >> Eric >>>>>> Obviously one can wonder if this variability is something normal >>>>>> and does not hide any other bug. I hope this series will raise >>>>>> additional discussions about this. >>>>>> >>>>>> https://github.com/eauger/kut/tree/pmu-chain-promotion-fixes-v1 >>>>> Gentle ping. >>>> I'd be happy to take this, but I was hoping to see some r-b's and/or t-b's >>>> from some of the others. >>> I gave this a spin on my ThunderX2, and it seems to fix the intermittent >>> failures I was seeing. >>> >>> FWIW: >>> >>> Tested-by: Mark Rutland <mark.rutland@xxxxxxx> >>> >>> Before (on commit 4ba7058c61e8922f9c8397cfa1095fac325f809b): >>> >>> Test results below. >>> >>> | [mark@gravadlaks:~/src/kvm-unit-tests]% TESTNAME=pmu-chain-promotion TIMEOUT=90s ACCEL= useapp qemu ./arm/run arm/pmu.flat -smp 1 -append 'pmu-chain-promotion' >>> | timeout -k 1s --foreground 90s /home/mark/.opt/apps/qemu/bin/qemu-system-aarch64 -nodefaults -machine virt,gic-version=host -accel kvm -cpu host -device virtio-serial-device -device virtconsole,chardev=ctd -chardev testdev,id=ctd -device pci-testdev -display none -serial stdio -kernel arm/pmu.flat -smp 1 -append pmu-chain-promotion # -initrd /tmp/tmp.nl1i6S0EIY >>> | INFO: PMU version: 0x4 >>> | INFO: PMU implementer/ID code: 0(" ")/0 >>> | INFO: Implements 6 event counters >>> | PASS: pmu: pmu-chain-promotion: 32-bit overflows: chain counter not counting if even counter is disabled >>> | PASS: pmu: pmu-chain-promotion: 32-bit overflows: odd counter did not increment on overflow if disabled >>> | INFO: pmu: pmu-chain-promotion: 32-bit overflows: MEM_ACCESS counter #0 has value 0x7 >>> | INFO: pmu: pmu-chain-promotion: 32-bit overflows: CHAIN counter #1 has value 0x0 >>> | INFO: pmu: pmu-chain-promotion: 32-bit overflows: overflow counter 0x1 >>> | INFO: pmu: pmu-chain-promotion: 32-bit overflows: MEM_ACCESS counter #0 has value 0x4 >>> | INFO: pmu: pmu-chain-promotion: 32-bit overflows: MEM_ACCESS counter #0 has value 0x1b >>> | PASS: pmu: pmu-chain-promotion: 32-bit overflows: should have triggered an overflow on #0 >>> | FAIL: pmu: pmu-chain-promotion: 32-bit overflows: CHAIN counter #1 shouldn't have incremented >>> | INFO: pmu: pmu-chain-promotion: 32-bit overflows: counter #0 = 0xffffffdc, counter #1 = 0x0 overflow=0x0 >>> | INFO: pmu: pmu-chain-promotion: 32-bit overflows: MEM_ACCESS counter #0 has value 0x4 >>> | INFO: pmu: pmu-chain-promotion: 32-bit overflows: MEM_ACCESS counter #0 has value 0x1b >>> | FAIL: pmu: pmu-chain-promotion: 32-bit overflows: CHAIN counter enabled: CHAIN counter was incremented and overflow >>> | INFO: pmu: pmu-chain-promotion: 32-bit overflows: CHAIN counter #1 = 0x0, overflow=0x1 >>> | INFO: pmu: pmu-chain-promotion: 32-bit overflows: MEM_ACCESS counter #0 has value 0x4 >>> | INFO: pmu: pmu-chain-promotion: 32-bit overflows: MEM_ACCESS counter #0 has value 0x1b >>> | FAIL: pmu: pmu-chain-promotion: 32-bit overflows: 32b->64b: CHAIN counter incremented and overflow >>> | INFO: pmu: pmu-chain-promotion: 32-bit overflows: CHAIN counter #1 = 0x0, overflow=0x1 >>> | INFO: pmu: pmu-chain-promotion: 32-bit overflows: counter #0=0xfffffff3, counter #1=0x0 >>> | PASS: pmu: pmu-chain-promotion: 32-bit overflows: overflow is expected on counter 0 >>> | INFO: pmu: pmu-chain-promotion: 32-bit overflows: counter #0=0xa, counter #1=0xf9 overflow=0x1 >>> | SUMMARY: 7 tests, 3 unexpected failures >>> >>> After: >>> >>> | [mark@gravadlaks:~/src/kvm-unit-tests]% TESTNAME=pmu-chain-promotion TIMEOUT=90s ACCEL=kvm useapp qemu ./arm/run arm/pmu.flat -smp 1 -append 'pmu-chain-promotion' >>> | timeout -k 1s --foreground 90s /home/mark/.opt/apps/qemu/bin/qemu-system-aarch64 -nodefaults -machine virt,gic-version=host -accel kvm -cpu host -device virtio-serial-device -device virtconsole,chardev=ctd -chardev testdev,id=ctd -device pci-testdev -display none -serial stdio -kernel arm/pmu.flat -smp 1 -append pmu-chain-promotion # -initrd /tmp/tmp.pahLyg1F3s >>> | INFO: PMU version: 0x4 >>> | INFO: PMU implementer/ID code: 0(" ")/0 >>> | INFO: Implements 6 event counters >>> | INFO: pmu: pmu-chain-promotion: 32-bit overflows: subtest1: post #1=0x0 #0=0x0 overflow=0x0 >>> | PASS: pmu: pmu-chain-promotion: 32-bit overflows: subtest1: chain counter not counting if even counter is disabled >>> | INFO: pmu: pmu-chain-promotion: 32-bit overflows: subtest2: post #1=0x0 #0=0xf3 overflow=0x1 >>> | PASS: pmu: pmu-chain-promotion: 32-bit overflows: subtest2: odd counter did not increment on overflow if disabled >>> | INFO: pmu: pmu-chain-promotion: 32-bit overflows: subtest3: init #1=0x0 #0=0xfffffea1 overflow=0x0 >>> | INFO: pmu: pmu-chain-promotion: 32-bit overflows: subtest3: After 1st loop #1=0x0 #0=0xffffffa0 overflow=0x0 >>> | INFO: pmu: pmu-chain-promotion: 32-bit overflows: subtest3: After 2d loop #1=0x0 #0=0xc0 overflow=0x1 >>> | PASS: pmu: pmu-chain-promotion: 32-bit overflows: subtest3: should have triggered an overflow on #0 >>> | PASS: pmu: pmu-chain-promotion: 32-bit overflows: subtest3: CHAIN counter #1 shouldn't have incremented >>> | INFO: pmu: pmu-chain-promotion: 32-bit overflows: subtest4: init #1=0x0 #0=0xfffffea1 overflow=0x0 >>> | INFO: pmu: pmu-chain-promotion: 32-bit overflows: subtest4: After 1st loop #1=0x0 #0=0xffffffb7 overflow=0x0 >>> | INFO: pmu: pmu-chain-promotion: 32-bit overflows: subtest4: After 2d loop #1=0x1 #0=0xbc overflow=0x1 >>> | PASS: pmu: pmu-chain-promotion: 32-bit overflows: subtest4: CHAIN counter enabled: CHAIN counter was incremented and overflow >>> | INFO: pmu: pmu-chain-promotion: 32-bit overflows: subtest5: init #1=0x0 #0=0xfffffea1 overflow=0x0 >>> | INFO: pmu: pmu-chain-promotion: 32-bit overflows: subtest5: After 1st loop #1=0x22c #0=0xffffff9f overflow=0x0 >>> | INFO: pmu: pmu-chain-promotion: 32-bit overflows: subtest5: After 2d loop #1=0x1 #0=0x9d overflow=0x1 >>> | PASS: pmu: pmu-chain-promotion: 32-bit overflows: subtest5: 32b->64b: CHAIN counter incremented and overflow >>> | INFO: pmu: pmu-chain-promotion: 32-bit overflows: subtest6: init #1=0x0 #0=0xfffffea1 overflow=0x0 >>> | INFO: pmu: pmu-chain-promotion: 32-bit overflows: subtest6: After 1st loop #1=0x0 #0=0xffffff9f overflow=0x0 >>> | INFO: pmu: pmu-chain-promotion: 32-bit overflows: subtest6: After 2d loop #1=0x1f9 #0=0x9c overflow=0x1 >>> | PASS: pmu: pmu-chain-promotion: 32-bit overflows: subtest6: overflow is expected on counter 0 >>> | SUMMARY: 7 tests >>> >>> As a bonus, the mem-access and memaccess-reliability results: >>> >>> | [mark@gravadlaks:~/src/kvm-unit-tests]% TESTNAME=pmu-chain-promotion TIMEOUT=90s ACCEL=kvm useapp qemu ./arm/run arm/pmu.flat -smp 1 -append 'pmu-mem-access' >>> | timeout -k 1s --foreground 90s /home/mark/.opt/apps/qemu/bin/qemu-system-aarch64 -nodefaults -machine virt,gic-version=host -accel kvm -cpu host -device virtio-serial-device -device virtconsole,chardev=ctd -chardev testdev,id=ctd -device pci-testdev -display none -serial stdio -kernel arm/pmu.flat -smp 1 -append pmu-mem-access # -initrd /tmp/tmp.84AeEp8Tiw >>> | INFO: PMU version: 0x4 >>> | INFO: PMU implementer/ID code: 0(" ")/0 >>> | INFO: Implements 6 event counters >>> | INFO: pmu: pmu-mem-access: 32-bit overflows: counter #0 is 0x15 (MEM_ACCESS) >>> | INFO: pmu: pmu-mem-access: 32-bit overflows: counter #1 is 0x15 (MEM_ACCESS) >>> | PASS: pmu: pmu-mem-access: 32-bit overflows: Ran 20 mem accesses >>> | PASS: pmu: pmu-mem-access: 32-bit overflows: Ran 20 mem accesses with expected overflows on both counters >>> | INFO: pmu: pmu-mem-access: 32-bit overflows: cnt#0=0x8 cnt#1=0x8 overflow=0x3 >>> | SKIP: pmu: pmu-mem-access: 64-bit overflows: Skip test as 64 overflows need FEAT_PMUv3p5 >>> | SUMMARY: 3 tests, 1 skipped >>> | [mark@gravadlaks:~/src/kvm-unit-tests]% TESTNAME=pmu-chain-promotion TIMEOUT=90s ACCEL=kvm useapp qemu ./arm/run arm/pmu.flat -smp 1 -append 'pmu-memaccess-reliability' >>> | timeout -k 1s --foreground 90s /home/mark/.opt/apps/qemu/bin/qemu-system-aarch64 -nodefaults -machine virt,gic-version=host -accel kvm -cpu host -device virtio-serial-device -device virtconsole,chardev=ctd -chardev testdev,id=ctd -device pci-testdev -display none -serial stdio -kernel arm/pmu.flat -smp 1 -append pmu-memaccess-reliability # -initrd /tmp/tmp.ZToqwencZR >>> | INFO: PMU version: 0x4 >>> | INFO: PMU implementer/ID code: 0(" ")/0 >>> | INFO: Implements 6 event counters >>> | INFO: pmu: pmu-memaccess-reliability: 32-bit overflows: overflow=0 min=251 max=283 COUNT=250 MARGIN=100 >>> | PASS: pmu: pmu-memaccess-reliability: 32-bit overflows: memaccess is reliable >>> | SKIP: pmu: pmu-memaccess-reliability: 64-bit overflows: Skip test as 64 overflows need FEAT_PMUv3p5 >>> | SUMMARY: 2 tests, 1 skipped >>> >>> Thanks, >>> Mark. >>>
