Re: POC: Cache data in GetSnapshotData()
| От | Amit Kapila |
|---|---|
| Тема | Re: POC: Cache data in GetSnapshotData() |
| Дата | |
| Msg-id | CAA4eK1LBOQ4e3Ycge+Fe0euzVu89CqGTuGNeajOienxJR0AEKA@mail.gmail.com обсуждение исходный текст |
| Ответ на | Re: POC: Cache data in GetSnapshotData() (Robert Haas <robertmhaas@gmail.com>) |
| Ответы |
Re: POC: Cache data in GetSnapshotData()
|
| Список | pgsql-hackers |
On Wed, Mar 16, 2016 at 10:59 PM, Robert Haas <robertmhaas@gmail.com> wrote:
On Wed, Mar 16, 2016 at 4:40 AM, Mithun Cy <mithun.cy@enterprisedb.com> wrote:On Thu, Mar 3, 2016 at 6:20 AM, Mithun Cy <mithun.cy@enterprisedb.com> wrote:
> I will continue to benchmark above tests with much wider range of clients.Latest Benchmarking shows following results for unlogged tables.
clients BASE ONLY CLOG CHANGES % Increase CLOG CHANGES + SAVE SNAPSHOT % Increase 1 1198.326337 1328.069656 10.8270439357 1234.078342 2.9834948875 32 37455.181727 38295.250519 2.2428640131 41023.126293 9.5259037641 64 48838.016451 50675.845885 3.7631123611 51662.814319 5.7840143259 88 36878.187766 53173.577363 44.1870671639 56025.454917 51.9203038731 128 35901.537773 52026.024098 44.9130798434 53864.486733 50.0339263281 256 28130.354402 46793.134156 66.3439197647 46817.04602 66.4289235427 Whoa. At 64 clients, we're hardly getting any benefit, but then by 88 clients, we're getting a huge benefit. I wonder why there's that sharp change there.
If you see, for the Base readings, there is a performance increase up till 64 clients and then there is a fall at 88 clients, which to me indicates that it hits very high-contention around CLogControlLock at 88 clients which CLog patch is able to control to a great degree (if required, I think the same can be verified by LWLock stats data). One reason for hitting contention at 88 clients is that this machine seems to have 64-cores (it has 8 sockets and 8 Core(s) per socket) as per below information of lscpu command.
Architecture: x86_64
CPU op-mode(s): 32-bit, 64-bit
Byte Order: Little Endian
CPU(s): 128
On-line CPU(s) list: 0-127
Thread(s) per core: 2
Core(s) per socket: 8
Socket(s): 8
NUMA node(s): 8
Vendor ID: GenuineIntel
CPU family: 6
Model: 47
Model name: Intel(R) Xeon(R) CPU E7- 8830 @ 2.13GHz
Stepping: 2
CPU MHz: 1064.000
BogoMIPS: 4266.62
Virtualization: VT-x
L1d cache: 32K
L1i cache: 32K
L2 cache: 256K
L3 cache: 24576K
NUMA node0 CPU(s): 0,65-71,96-103
NUMA node1 CPU(s): 72-79,104-111
NUMA node2 CPU(s): 80-87,112-119
NUMA node3 CPU(s): 88-95,120-127
NUMA node4 CPU(s): 1-8,33-40
NUMA node5 CPU(s): 9-16,41-48
NUMA node6 CPU(s): 17-24,49-56
NUMA node7 CPU(s): 25-32,57-64
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