Re: Move PinBuffer and UnpinBuffer to atomics

On Mon, Apr 11, 2016 at 5:04 PM, Alexander Korotkov <
a(dot)korotkov(at)postgrespro(dot)ru> wrote:

> On Mon, Apr 11, 2016 at 8:10 AM, Andres Freund <andres(at)anarazel(dot)de> wrote:
>
>> Could you retry after applying the attached series of patches?
>>
>
> Yes, I will try with these patches and snapshot too old reverted.
>

I've run the same benchmark with 279d86af and 848ef42b reverted. I've
tested of all 3 patches from you applied and, for comparison, 3 patches +
clog buffers reverted back to 32.

clients patches patches + clog_32
1 12594 12556
2 26705 26258
4 50985 53254
8 103234 104416
10 135321 130893
20 268675 267648
30 370437 409710
40 486512 482382
50 539910 525667
60 616401 672230
70 667864 660853
80 924606 737768
90 1217435 799581
100 1326054 863066
110 1446380 980206
120 1484920 1000963
130 1512440 1058852
140 1536181 1088958
150 1504750 1134354
160 1461513 1132173
170 1453943 1158656
180 1426288 1120511

I hardly can understand how clog buffers influence read-only benchmark. It
even harder for me why influence of clog buffers change its direction after
applying your patches. But the results are following. And I've rechecked
some values manually to verify that there is no error. I would be very
thankful for any explanation.

------
Alexander Korotkov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company