Hi Josef,
Looking at the latest Linus tree, I still see:
if (actual_count > 0) {
u64 runtime = ktime_to_ns(ktime_sub(ktime_get(), start));
...
avg = fs_info->avg_delayed_ref_runtime * 3 + runtime;
avg = div64_u64(avg, 4);
So we need to divide "runtime" by "actual_count" before accounting it
in "avg_delayed_ref_runtime"?
Thanks,
Alex.
On Thu, Feb 27, 2014 at 5:56 PM, Josef Bacik <jba...@fb.com> wrote:
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> On 02/27/2014 10:38 AM, 钱凯 wrote:
>> I'm a little confused of what "avg_delayed_ref_runtime" means.
>>
>> In __btrfs_run_delayed_refs(), "avg_delayed_ref_runtime" is set to
>> the runtime of all delayed refs processed in current transaction
>> commit. However, in btrfs_should_throttle_delayed_refs(), we based
>> on the following condition to decide whether throttle refs or not:
>> ***************************************** avg_runtime =
>> fs_info->avg_delayed_ref_runtime; if (num_entries * avg_runtime >=
>> NSEC_PER_SEC) return 1; *****************************************
>> It looks like "avg_delayed_ref_runtime" is used as runtime of each
>> delayed ref processed in average here. So what does it really
>> means?
>>
>
> Yeah I screwed this up, I should have been dividing the total time by
> the number of delayed refs I ran. I have a patch locally to fix it
> and I'll send it out after I finish my qgroup work. Thanks,
>
> Josef
>
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