Re: SLRU optimization - configurable buffer pool and partitioning the SLRU lock

On Thu, Feb 1, 2024 at 4:12 PM Dilip Kumar <dilipbalaut(at)gmail(dot)com> wrote:
>
> On Thu, Feb 1, 2024 at 3:44 PM Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org> wrote:

> Okay.
> >
> > While I have your attention -- if you could give a look to the 0001
> > patch I posted, I would appreciate it.
> >
>
> I will look into it. Thanks.

Some quick observations,

Do we need below two write barriers at the end of the function?
because the next instruction is separated by the function boundary

@@ -766,14 +766,11 @@ StartupCLOG(void)
..
- XactCtl->shared->latest_page_number = pageno;
-
- LWLockRelease(XactSLRULock);
+ pg_atomic_init_u64(&XactCtl->shared->latest_page_number, pageno);
+ pg_write_barrier();
}

/*
* Initialize member's idea of the latest page number.
*/
pageno = MXOffsetToMemberPage(offset);
- MultiXactMemberCtl->shared->latest_page_number = pageno;
+ pg_atomic_init_u64(&MultiXactMemberCtl->shared->latest_page_number,
+ pageno);
+
+ pg_write_barrier();
}

I am looking more into this from the concurrency point of view and
will update you soon.

--
Regards,
Dilip Kumar
EnterpriseDB: http://www.enterprisedb.com