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From: Haibo Xu <xiaobo55x@gmail.com>
To: Andrew Jones <ajones@ventanamicro.com>
Cc: Haibo Xu <haibo1.xu@intel.com>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	 Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	 Paolo Bonzini <pbonzini@redhat.com>,
	Shuah Khan <shuah@kernel.org>, Marc Zyngier <maz@kernel.org>,
	 Oliver Upton <oliver.upton@linux.dev>,
	James Morse <james.morse@arm.com>,
	 Suzuki K Poulose <suzuki.poulose@arm.com>,
	Zenghui Yu <yuzenghui@huawei.com>,
	 Anup Patel <anup@brainfault.org>,
	Atish Patra <atishp@atishpatra.org>,
	 Sean Christopherson <seanjc@google.com>,
	Ricardo Koller <ricarkol@google.com>,
	 Vishal Annapurve <vannapurve@google.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	 Vipin Sharma <vipinsh@google.com>,
	David Matlack <dmatlack@google.com>,
	 Colton Lewis <coltonlewis@google.com>,
	Aaron Lewis <aaronlewis@google.com>,
	 Thomas Huth <thuth@redhat.com>,
	linux-kernel@vger.kernel.org,  linux-riscv@lists.infradead.org,
	kvm@vger.kernel.org,  linux-kselftest@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,  kvmarm@lists.linux.dev,
	kvm-riscv@lists.infradead.org
Subject: Re: [PATCH v3 9/9] KVM: riscv: selftests: Add sstc timer test
Date: Mon, 4 Dec 2023 10:42:24 +0800	[thread overview]
Message-ID: <CAJve8omitHDpijJaLV_wHk+5LXpsBUWF8_eTD4MeWKM-807Siw@mail.gmail.com> (raw)
In-Reply-To: <CAJve8onhY534T=Hyncjfi4GfdZ+0D2xM+jRSaYCAWCdaKxPUcQ@mail.gmail.com>

On Fri, Sep 15, 2023 at 2:21 PM Haibo Xu <xiaobo55x@gmail.com> wrote:
>
> On Thu, Sep 14, 2023 at 5:52 PM Andrew Jones <ajones@ventanamicro.com> wrote:
> >
> > On Thu, Sep 14, 2023 at 09:37:03AM +0800, Haibo Xu wrote:
> > > Add a KVM selftests to validate the Sstc timer functionality.
> > > The test was ported from arm64 arch timer test.
> >
> > I just tried this test out. Running it over and over again on QEMU I see
> > it works sometimes, but it frequently fails with the
> > GUEST_ASSERT_EQ(config_iter + 1, irq_iter) assert and at least once I
> > also saw the __GUEST_ASSERT(xcnt >= cmp) assert.
> >
>
> Good catch!
>
> I can also reproduce this issue and it is a common problem for both
> arm64 and riscv because it also happens in a arm64 Qemu VM.
>
> It seems like a synchronization issue between host and guest shared
> variables. Will double check the test code.
>
> > Thanks,
> > drew

Hi Andrew,

After several rounds of regression testing, some findings:
1. The intermittent failure also happened on ARM64 Qemu VM, and even
in the initial arch_timer commit(4959d8650e9f4).
2. it didn't happen on a ARM64 HW(but a different failure occured
during stress test)
3. The failure have a close relationship with
TIMER_TEST_ERR_MARGIN_US(default 100), and after increasing
     the macro to 300, the failure couldn't reproduced in 1000 loops
stress test in RISC-V Qemu VM

So my suggestion is we can expose the TIMER_TEST_ERR_MARGIN_US
parameter as an arch_timer test arg parameter
and tune it based on a specific test environment.

What's your opinion?

Regards,
Haibo

  reply	other threads:[~2023-12-04  2:42 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-14  1:36 [PATCH v3 0/9] RISCV: Add kvm Sstc timer selftests Haibo Xu
2023-09-14  1:36 ` [PATCH v3 1/9] KVM: selftests: Unify the codes for guest exception handling Haibo Xu
2023-09-14  1:36 ` [PATCH v3 2/9] KVM: selftests: Unify the makefile rule for split targets Haibo Xu
2023-09-14  8:46   ` Andrew Jones
2023-10-03 10:28   ` Andrew Jones
2023-10-08  2:58     ` Haibo Xu
2023-11-22  8:13       ` Andrew Jones
2023-11-23  2:50         ` Haibo Xu
2023-09-14  1:36 ` [PATCH v3 3/9] KVM: arm64: selftests: Split arch_timer test code Haibo Xu
2023-09-14  8:43   ` Andrew Jones
2023-09-14  1:36 ` [PATCH v3 4/9] tools: riscv: Add header file csr.h Haibo Xu
2023-09-14  8:14   ` Andrew Jones
2023-09-15  6:08     ` Haibo Xu
2023-09-14  1:36 ` [PATCH v3 5/9] KVM: riscv: selftests: Switch to use macro from csr.h Haibo Xu
2023-09-14  8:52   ` Andrew Jones
2023-09-15  6:13     ` Haibo Xu
2023-09-14  1:37 ` [PATCH v3 6/9] KVM: riscv: selftests: Add exception handling support Haibo Xu
2023-09-14  1:37 ` [PATCH v3 7/9] KVM: riscv: selftests: Add guest helper to get vcpu id Haibo Xu
2023-09-14  1:37 ` [PATCH v3 8/9] KVM: riscv: selftests: Change vcpu_has_ext to a common function Haibo Xu
2023-09-14  9:05   ` Andrew Jones
2023-09-15  6:14     ` Haibo Xu
2023-09-14  1:37 ` [PATCH v3 9/9] KVM: riscv: selftests: Add sstc timer test Haibo Xu
2023-09-14  9:36   ` Andrew Jones
2023-09-14  9:52     ` Conor Dooley
2023-09-14 10:15       ` Andrew Jones
2023-09-15  6:23         ` Haibo Xu
2023-09-14  9:51   ` Andrew Jones
2023-09-15  6:21     ` Haibo Xu
2023-12-04  2:42       ` Haibo Xu [this message]
2023-12-04 11:32         ` Andrew Jones
2023-12-05  7:58           ` Haibo Xu

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