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. > > > 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.
