Re: asynchronous and vectorized execution

From: Kyotaro HORIGUCHI <horiguchi(dot)kyotaro(at)lab(dot)ntt(dot)co(dot)jp>
To: robertmhaas(at)gmail(dot)com
Cc: amitdkhan(dot)pg(at)gmail(dot)com, pgsql-hackers(at)postgresql(dot)org
Subject: Re: asynchronous and vectorized execution
Date: 2016-07-22 08:15:14
Message-ID: 20160722.171514.212990063.horiguchi.kyotaro@lab.ntt.co.jp
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The previous patch set doesn't accept --enable-cassert. The
attached additional one fixes it. It theoretically won't give
degradation but I'll measure the performance change.

At Thu, 21 Jul 2016 18:50:07 +0900 (Tokyo Standard Time), Kyotaro HORIGUCHI <horiguchi(dot)kyotaro(at)lab(dot)ntt(dot)co(dot)jp> wrote in <20160721(dot)185007(dot)268388411(dot)horiguchi(dot)kyotaro(at)lab(dot)ntt(dot)co(dot)jp>
> Hello,
>
> At Tue, 12 Jul 2016 11:42:55 +0900 (Tokyo Standard Time), Kyotaro HORIGUCHI <horiguchi(dot)kyotaro(at)lab(dot)ntt(dot)co(dot)jp> wrote in <20160712(dot)114255(dot)156540680(dot)horiguchi(dot)kyotaro(at)lab(dot)ntt(dot)co(dot)jp>
> After some refactoring, degradation for a simple seqscan is
> reduced to 1.4% and that of "Append(SeqScan())" is reduced to
> 1.7%. The gains are the same to the previous measurement. Scale
> has been changed from previous measurement in some test cases.
>
> t0- (SeqScan()) (2 parallel)
> pl- (Append(4 * SeqScan()))
> pf0 (Append(4 * ForeignScan())) all ForeignScans are on the same connection.
> pf1 (Append(4 * ForeignScan())) all ForeignScans have their own connections.
>
>
> patched-O2 time(ms) stddev(ms) gain from unpatched (%)
> t0 4121.27 1.1 -1.44
> pl 1757.41 0.94 -1.73
> pf0 6458.99 192.4 20.26
> pf1 1747.4 24.81 78.39
>
> unpatched-O2
> t0 4062.6 1.95
> pl 1727.45 9.41
> pf0 8100.47 24.51
> pf1 8086.52 33.53
>
> > > Addition to the aboves, I will try reentrant ExecAsyncWaitForNode
> > > or something.
>
> After some consideration, I found that ExecAsyncWaitForNode
> cannot be reentrant because it means that the control goes into
> async-unaware nodes while having not-ready nodes, that is
> inconsistent state. To inhibit such reentering, I allocated node
> identifiers in depth-first order so that ascendant-descendant
> relationship can be checked (nested-set model) in simple way and
> call ExecAsyncConfigureWait only for the descendant nodes of the
> parameter planstate.

--
Kyotaro Horiguchi
NTT Open Source Software Center

Attachment Content-Type Size
0008-Change-two-macros-into-inline-functions.patch text/x-patch 2.0 KB

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