From: Chao Li <li.evan.chao@gmail.com>
Message-Id: <56B09FF0-13AB-4AF3-A4C4-29428A695FB0@gmail.com>
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Subject: Re: pg_test_timing: fix unit typo and widen diff type
Date: Wed, 22 Apr 2026 16:57:32 +0800
In-Reply-To: 
 <CAHGQGwEM=s5vXPpXoismwRMNCnAmwwMJPnQEQYbPFTJGouV0rQ@mail.gmail.com>
Cc: "wang.xiao.peng" <wxp_728@163.com>,
 lukas@fittl.com,
 PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>,
 Tom Lane <tgl@sss.pgh.pa.us>,
 Hannu Krosing <hannuk@google.com>
To: Fujii Masao <masao.fujii@gmail.com>
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 <7d4afbdb.5322.19d70df0de4.Coremail.wxp_728@163.com>
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> On Apr 22, 2026, at 15:04, Fujii Masao <masao.fujii@gmail.com> wrote:
>=20
> On Thu, Apr 9, 2026 at 3:13=E2=80=AFPM wang.xiao.peng =
<wxp_728@163.com> wrote:
>> Just finished reviewing the v3 patches - looks good to me. The =
pg_leftmost_one_pos64 fix is spot on, and using INT64_FORMAT for the =
error message is the right approach.
>=20
> Since pg_leftmost_one_pos64() can return up to 63, should the size of
> histogram[] be changed from 32 to 64? If we want to display the full
> histogram[] in the output, max_bit in output() would also need to be =
set to 63.
> Alternatively, it may be fine to keep max_bit =3D 31 and show only
> the first 32 histogram entries.

I revisited this patch and think it makes sense to extend histogram[] to =
64 entries.

In practice, the higher buckets will almost always remain zero, and =
output() already omits trailing histogram entries with zero counts, so =
this change is unlikely to affect the actual runtime output in normal =
cases.

Accordingly, I also adjusted the minimum width of the first column, =
since the maximum int64 value has 19 digits, and updated the printf =
format accordingly.

>=20
> Patch 0001 looks good to me.

Cool.

PFA v4:

* 0001 unchanged from v3.
* 0002 changed size of histogram[] 64.

Best regards,
--
Chao Li (Evan)
HighGo Software Co., Ltd.
https://www.highgo.com/


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b/src/bin/pg_test_timing/pg_test_timing.c=0A@@=20-18,14=20+18,14=20@@=20=
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max_rprct=20=3D=2099.99;=0A=20=0A=20/*=20record=20duration=20in=20powers=20=
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pg_leftmost_one_pos32(diff)=20+=201;=0A+=09=09{=0A+=09=09=09bits=20=3D=20=
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duration,=20TimingClockSourceType=20source,=20bool=20fast_timin=0A=20=
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max_bit=20=3D=2031;=0A+=09int=09=09=09max_bit=20=3D=20=
lengthof(histogram)=20-=201;=0A=20=09const=20char=20*header1=20=3D=20=
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=3D=20(double)=20histogram[i]=20*=20100=20/=20loop_count;=0A=20=0A=20=09=09=
rprct=20+=3D=20prct;=0A-=09=09printf("%*ld=20=20=20%*.4f=20%*.4f=20=
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=20=20len4,=20largest_diff_count);=0A--=20=0A2.50.1=20(Apple=20Git-155)=0A=
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