Re: Improving connection scalability: GetSnapshotData() - Mailing list pgsql-hackers

From Konstantin Knizhnik
Subject Re: Improving connection scalability: GetSnapshotData()
Date
Msg-id d2e395ba-372c-9e36-61d7-6b2b27b19ccb@postgrespro.ru
Whole thread Raw
In response to Re: Improving connection scalability: GetSnapshotData()  (Andres Freund <andres@anarazel.de>)
List pgsql-hackers

On 06.09.2020 21:52, Andres Freund wrote:
> Hi,
>
> On 2020-09-05 16:58:31 +0300, Konstantin Knizhnik wrote:
>> On 04.09.2020 21:53, Andres Freund wrote:
>>> I also used huge_pages=on / configured them on the OS level. Otherwise
>>> TLB misses will be a significant factor.
>> As far as I understand there should not be no any TLB misses because size of
>> the shared buffers (8Mb) as several order of magnitude smaler that available
>> physical memory.
> I assume you didn't mean 8MB but 8GB? If so, that's way large enough to
> be bigger than the TLB, particularly across processes (IIRC there's no
> optimization to keep shared mappings de-duplicated between processes
> from the view of the TLB).
>
>
Sorry, certainly 8Gb.
I tried huge pages, but it has almost no effect/



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