Hi Akira,
Thanks a lot for commenting on the patch. Just sent the patch version 2.
Cheers!
--Jason
On Tue, May 16, 2017 at 11:05 PM, Akira Yokosawa <akiyks@xxxxxxxxx> wrote:
> On 2017/05/16 22:04:59 +0800, Junchang Wang wrote:
>> Hi Paul and Akira,
>>
>> This is the updated patch according to the discussion with Akira and
>> following is the summary. Please take a look. Comments are welcome!
>>
>> In function eventual( ), if the value of stopflag become larger than
>> zero (the ''if'' branch is taken), then only the "eventual()" thread
>> updates stopflag. So, the READ_ONCE() within the WRITE_ONCE() is not
>> necessary. Remove it.
>> In function count_cleanup( ), there is no need to run smp_mb( ) in
>> between statement writing to and statement reading from the same
>> variable, stopflag. Remove smp_mb().
>>
>>
>> Thanks,
>> --Jason
>>
>> On Tue, May 16, 2017 at 9:40 PM, Junchang Wang <junchangwang@xxxxxxxxx> wrote:
>>> Signed-off-by: Junchang Wang <junchangwang@xxxxxxxxx>
>>> Signed-off-by: Akira Yokosawa <akiyks@xxxxxxxxx>
>
> Hi Jason,
>
> Glad to know you agree with me here!
>
> Can you resubmit a v2 of the patch to include the message above in the commit
> log? It would be easier for Paul to apply.
> Also, since I didn't created the patch itself, I'd like you to use the following
> tag instead:
>
> Suggested-by: Akira Yokosawa <akiyks@xxxxxxxxx>
>
> in front of your Signed-off-by.
>
> Thanks, Akira
>
>>> ---
>>> CodeSamples/count/count_stat_eventual.c | 8 ++++----
>>> 1 file changed, 4 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/CodeSamples/count/count_stat_eventual.c b/CodeSamples/count/count_stat_eventual.c
>>> index 464de30..1365168 100644
>>> --- a/CodeSamples/count/count_stat_eventual.c
>>> +++ b/CodeSamples/count/count_stat_eventual.c
>>> @@ -40,16 +40,17 @@ void *eventual(void *arg)
>>> {
>>> int t;
>>> unsigned long sum;
>>> + int stopflag_l = 0;
>>>
>>> - while (READ_ONCE(stopflag) < 3) {
>>> + while (stopflag_l < 3) {
>>> sum = 0;
>>> for_each_thread(t)
>>> sum += READ_ONCE(per_thread(counter, t));
>>> WRITE_ONCE(global_count, sum);
>>> poll(NULL, 0, 1);
>>> - if (READ_ONCE(stopflag)) {
>>> + if ((stopflag_l = READ_ONCE(stopflag)) != 0) {
>>> smp_mb();
>>> - WRITE_ONCE(stopflag, READ_ONCE(stopflag) + 1);
>>> + WRITE_ONCE(stopflag, ++stopflag_l);
>>> }
>>> }
>>> return NULL;
>>> @@ -68,7 +69,6 @@ void count_init(void)
>>> void count_cleanup(void)
>>> {
>>> WRITE_ONCE(stopflag, 1);
>>> - smp_mb();
>>> while (READ_ONCE(stopflag) < 3)
>>> poll(NULL, 0, 1);
>>> smp_mb();
>>> --
>>> 2.7.4
>>>
>>
>
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