Re: LWLock cache line alignment - Mailing list pgsql-hackers

From Tom Lane
Subject Re: LWLock cache line alignment
Date
Msg-id 16463.1107446569@sss.pgh.pa.us
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In response to Re: LWLock cache line alignment  ("Simon Riggs" <simon@2ndquadrant.com>)
Responses Re: LWLock cache line alignment  ("Simon Riggs" <simon@2ndquadrant.com>)
List pgsql-hackers
"Simon Riggs" <simon@2ndquadrant.com> writes:
>> From: Tom Lane [mailto:tgl@sss.pgh.pa.us] wrote
>> I've looked at this before and I think it's a nonstarter;
>> increasing the
>> size of a spinlock to 128 bytes is just not reasonable.

> Well, the performance is unreasonably poor, so its time to do something,
> which might if it is unreasonable for the general case would need to be
> port specific.

Well, it might be worth allocating a full 128 bytes just for the fixed
LWLocks (BufMgrLock and friends) and skimping on the per-buffer locks,
which should be seeing far less contention than the fixed locks anyway.
But first lets see some evidence that this actually helps?
        regards, tom lane


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