Re: [PATCH 2/6] KVM: selftests: Avoid flooding debug log while populating memory

2021-01-15 Thread Sean Christopherson 
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 
> 
> Signed-off-by: Ben Gardon 
> ---
>  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
>

Re: [PATCH 2/6] KVM: selftests: Avoid flooding debug log while populating memory

2021-01-12 Thread Thomas Huth 

On 12/01/2021 22.42, 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.

Reviewed-by: Jacob Xu 

Signed-off-by: Ben Gardon 
---
  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)
+   ;
}
  
  		ts_diff = timespec_elapsed(start);




Reviewed-by: Thomas Huth

[PATCH 2/6] KVM: selftests: Avoid flooding debug log while populating memory

2021-01-12 Thread Ben Gardon 
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.

Reviewed-by: Jacob Xu 

Signed-off-by: Ben Gardon 
---
 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)
+   ;
}
 
ts_diff = timespec_elapsed(start);
-- 
2.30.0.284.gd98b1dd5eaa7-goog