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    SubjectRe: [PATCH 2/6] KVM: selftests: Avoid flooding debug log while populating memory
    On Tue, Jan 12, 2021, Ben Gardon wrote:
    > Peter Xu pointed out that a log message printed while waiting for the
    > memory population phase of the dirty_log_perf_test will flood the debug
    > logs as there is no delay after printing the message. Since the message
    > does not provide much value anyway, remove it.

    Does it provide value if something goes wrong? E.g. if a vCPU doesn't finish,
    how would one go about debugging? Would it make sense to make the print
    ratelimited instead of removing it altogether?

    > Reviewed-by: Jacob Xu <jacobhxu@google.com>
    >
    > Signed-off-by: Ben Gardon <bgardon@google.com>
    > ---
    > tools/testing/selftests/kvm/dirty_log_perf_test.c | 9 ++++-----
    > 1 file changed, 4 insertions(+), 5 deletions(-)
    >
    > diff --git a/tools/testing/selftests/kvm/dirty_log_perf_test.c b/tools/testing/selftests/kvm/dirty_log_perf_test.c
    > index 16efe6589b43..15a9c45bdb5f 100644
    > --- a/tools/testing/selftests/kvm/dirty_log_perf_test.c
    > +++ b/tools/testing/selftests/kvm/dirty_log_perf_test.c
    > @@ -146,8 +146,7 @@ static void run_test(enum vm_guest_mode mode, void *arg)
    > /* Allow the vCPU to populate memory */
    > pr_debug("Starting iteration %lu - Populating\n", iteration);
    > while (READ_ONCE(vcpu_last_completed_iteration[vcpu_id]) != iteration)
    > - pr_debug("Waiting for vcpu_last_completed_iteration == %lu\n",
    > - iteration);
    > + ;
    >
    > ts_diff = timespec_elapsed(start);
    > pr_info("Populate memory time: %ld.%.9lds\n",
    > @@ -171,9 +170,9 @@ static void run_test(enum vm_guest_mode mode, void *arg)
    >
    > pr_debug("Starting iteration %lu\n", iteration);
    > for (vcpu_id = 0; vcpu_id < nr_vcpus; vcpu_id++) {
    > - while (READ_ONCE(vcpu_last_completed_iteration[vcpu_id]) != iteration)
    > - pr_debug("Waiting for vCPU %d vcpu_last_completed_iteration == %lu\n",
    > - vcpu_id, iteration);
    > + while (READ_ONCE(vcpu_last_completed_iteration[vcpu_id])
    > + != iteration)

    I like the original better. Poking out past 80 chars isn't the end of the world.

    > + ;
    > }
    >
    > ts_diff = timespec_elapsed(start);
    > --
    > 2.30.0.284.gd98b1dd5eaa7-goog
    >

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