From: Sean Christopherson <seanjc@google.com>
To: Anish Moorthy <amoorthy@google.com>
Cc: oliver.upton@linux.dev, maz@kernel.org, kvm@vger.kernel.org,
kvmarm@lists.linux.dev, robert.hoo.linux@gmail.com,
jthoughton@google.com, dmatlack@google.com,
axelrasmussen@google.com, peterx@redhat.com,
nadav.amit@gmail.com, isaku.yamahata@gmail.com,
kconsul@linux.vnet.ibm.com
Subject: Re: [PATCH v7 10/14] KVM: selftests: Report per-vcpu demand paging rate from demand paging test
Date: Tue, 9 Apr 2024 15:49:25 -0700 [thread overview]
Message-ID: <ZhXF9QTBgKHVO0ay@google.com> (raw)
In-Reply-To: <20240215235405.368539-11-amoorthy@google.com>
On Thu, Feb 15, 2024, Anish Moorthy wrote:
> Using the overall demand paging rate to measure performance can be
> slightly misleading when vCPU accesses are not overlapped. Adding more
> vCPUs will (usually) increase the overall demand paging rate even
> if performance remains constant or even degrades on a per-vcpu basis. As
> such, it makes sense to report both the total and per-vcpu paging rates.
>
> Signed-off-by: Anish Moorthy <amoorthy@google.com>
> ---
> tools/testing/selftests/kvm/demand_paging_test.c | 15 +++++++++++----
> 1 file changed, 11 insertions(+), 4 deletions(-)
>
> diff --git a/tools/testing/selftests/kvm/demand_paging_test.c b/tools/testing/selftests/kvm/demand_paging_test.c
> index 09c116a82a84..6dc823fa933a 100644
> --- a/tools/testing/selftests/kvm/demand_paging_test.c
> +++ b/tools/testing/selftests/kvm/demand_paging_test.c
> @@ -135,6 +135,7 @@ static void run_test(enum vm_guest_mode mode, void *arg)
> struct timespec ts_diff;
> struct kvm_vm *vm;
> int i;
> + double vcpu_paging_rate;
>
> vm = memstress_create_vm(mode, nr_vcpus, guest_percpu_mem_size, 1,
> p->src_type, p->partition_vcpu_memory_access);
> @@ -191,11 +192,17 @@ static void run_test(enum vm_guest_mode mode, void *arg)
> uffd_stop_demand_paging(uffd_descs[i]);
> }
>
> - pr_info("Total guest execution time: %ld.%.9lds\n",
> + pr_info("Total guest execution time:\t%ld.%.9lds\n",
> ts_diff.tv_sec, ts_diff.tv_nsec);
> - pr_info("Overall demand paging rate: %f pgs/sec\n",
> - memstress_args.vcpu_args[0].pages * nr_vcpus /
> - ((double)ts_diff.tv_sec + (double)ts_diff.tv_nsec / NSEC_PER_SEC));
> +
> + vcpu_paging_rate =
> + memstress_args.vcpu_args[0].pages
> + / ((double)ts_diff.tv_sec
> + + (double)ts_diff.tv_nsec / NSEC_PER_SEC);
*sigh*
For the umpteenth time, please follow kernel coding style. Either
vcpu_paging_rate = memstress_args.vcpu_args[0].pages /
((double)ts_diff.tv_sec + (double)ts_diff.tv_nsec / NSEC_PER_SEC);
or
vcpu_paging_rate = memstress_args.vcpu_args[0].pages /
((double)ts_diff.tv_sec +
(double)ts_diff.tv_nsec / NSEC_PER_SEC);
I don't have a strong preference, so I'll go with the first one when applying.
next prev parent reply other threads:[~2024-04-09 22:49 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-15 23:53 [PATCH v7 00/14] Improve KVM + userfaultfd performance via KVM_EXIT_MEMORY_FAULTs on stage-2 faults Anish Moorthy
2024-02-15 23:53 ` [PATCH v7 01/14] KVM: Clarify meaning of hva_to_pfn()'s 'atomic' parameter Anish Moorthy
2024-02-15 23:53 ` [PATCH v7 02/14] KVM: Add function comments for __kvm_read/write_guest_page() Anish Moorthy
2024-02-15 23:53 ` [PATCH v7 03/14] KVM: Documentation: Make note of the KVM_MEM_GUEST_MEMFD memslot flag Anish Moorthy
2024-04-09 22:47 ` Sean Christopherson
2024-02-15 23:53 ` [PATCH v7 04/14] KVM: Simplify error handling in __gfn_to_pfn_memslot() Anish Moorthy
2024-04-09 22:44 ` Sean Christopherson
2024-02-15 23:53 ` [PATCH v7 05/14] KVM: Define and communicate KVM_EXIT_MEMORY_FAULT RWX flags to userspace Anish Moorthy
2024-02-15 23:53 ` [PATCH v7 06/14] KVM: Add memslot flag to let userspace force an exit on missing hva mappings Anish Moorthy
2024-03-08 22:07 ` Sean Christopherson
2024-03-09 0:46 ` David Matlack
2024-03-11 4:45 ` Oliver Upton
2024-03-11 16:20 ` David Matlack
2024-03-11 16:36 ` Sean Christopherson
2024-03-11 17:08 ` Anish Moorthy
2024-03-11 21:21 ` Oliver Upton
2024-02-15 23:53 ` [PATCH v7 07/14] KVM: x86: Enable KVM_CAP_EXIT_ON_MISSING and annotate EFAULTs from stage-2 fault handler Anish Moorthy
2024-02-15 23:53 ` [PATCH v7 08/14] KVM: arm64: Enable KVM_CAP_MEMORY_FAULT_INFO and annotate fault in the " Anish Moorthy
2024-03-04 20:00 ` Oliver Upton
2024-03-04 20:10 ` Oliver Upton
2024-03-04 20:32 ` Sean Christopherson
2024-03-04 21:03 ` Oliver Upton
2024-03-04 22:49 ` Sean Christopherson
2024-03-05 1:01 ` Oliver Upton
2024-03-05 15:39 ` Sean Christopherson
2024-02-15 23:54 ` [PATCH v7 09/14] KVM: arm64: Implement and advertise KVM_CAP_EXIT_ON_MISSING Anish Moorthy
2024-02-15 23:54 ` [PATCH v7 10/14] KVM: selftests: Report per-vcpu demand paging rate from demand paging test Anish Moorthy
2024-04-09 22:49 ` Sean Christopherson [this message]
2024-02-15 23:54 ` [PATCH v7 11/14] KVM: selftests: Allow many vCPUs and reader threads per UFFD in " Anish Moorthy
2024-04-09 22:58 ` Sean Christopherson
2024-02-15 23:54 ` [PATCH v7 12/14] KVM: selftests: Use EPOLL in userfaultfd_util reader threads and signal errors via TEST_ASSERT Anish Moorthy
2024-02-15 23:54 ` [PATCH v7 13/14] KVM: selftests: Add memslot_flags parameter to memstress_create_vm() Anish Moorthy
2024-02-15 23:54 ` [PATCH v7 14/14] KVM: selftests: Handle memory fault exits in demand_paging_test Anish Moorthy
2024-02-16 7:36 ` [PATCH v7 00/14] Improve KVM + userfaultfd performance via KVM_EXIT_MEMORY_FAULTs on stage-2 faults Gupta, Pankaj
2024-02-16 20:00 ` Anish Moorthy
2024-02-16 23:40 ` Axel Rasmussen
2024-02-21 7:35 ` Gupta, Pankaj
2024-04-10 0:19 ` Sean Christopherson
2024-05-07 17:38 ` Anish Moorthy
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