From: "Jun. T" <takimoto-j@kba.biglobe.ne.jp>
To: zsh-workers@zsh.org
Subject: Re: ZSH performance regression in 5.8.1.2-test
Date: Thu, 28 Apr 2022 01:18:37 +0900 [thread overview]
Message-ID: <05F08D90-85FB-4A92-BC57-B56EA4177EC6@kba.biglobe.ne.jp> (raw)
In-Reply-To: <CAH+w=7bhgAtXnT5xTDS+d=y0ea6pAXbPMUoUQ27vyk6JXTGL1Q@mail.gmail.com>
> 2022/04/28 0:25, Bart Schaefer <schaefer@brasslantern.com> wrote:
>
> On Wed, Apr 27, 2022 at 7:00 AM Jun T <takimoto-j@kba.biglobe.ne.jp> wrote:
>>
>> (3) time zsh -f < tmp.txt
>
> Does it matter to (3) if "zsh -fs" ?
No, no noticeable difference.
>> With lseek() patch we get "reasonable" performance for (1)-(4).
>> (3) is somewhat slower, because it is reading form stdin and
>> need to call lseek() many times.
>
> I wonder if it would help to read less than SHINBUFSIZE when
> SHINSTDIN. E.g., make some guess at the "average line length" and
> read that many bytes. Might cause more calls to memchr() but less I/O
> (and shorter lseek()s, if that matters).
I tried setting SHINBUFSIZE to 80 for (3) (with lseek() patch):
SHINBUFSIZE=8192 about 1.3 sec
SHINBUFSIZE=80 about 1.2 sec (slight improvement)
(I'm now using a different Mac from the one used in the previous post)
I guess data is cached by the OS and read() is, in most cases, something
like memcpy(). I was running the test on a internal SDD of my iMac, but
running the test on a external HDD gives almost the same results.
If the file is on a "much slower" filesystem then the difference may be
somewhat larger.
next prev parent reply other threads:[~2022-04-27 16:19 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-25 18:16 Jordan Patterson
2022-04-25 18:56 ` Bart Schaefer
2022-04-25 19:20 ` Stephane Chazelas
2022-04-25 21:27 ` Bart Schaefer
2022-04-26 7:01 ` Bart Schaefer
2022-04-26 8:31 ` Peter Stephenson
2022-04-27 0:33 ` Bart Schaefer
2022-04-27 14:11 ` Stephane Chazelas
2022-04-27 15:02 ` Bart Schaefer
2022-04-27 15:07 ` Peter Stephenson
2022-04-27 15:17 ` Bart Schaefer
2022-04-26 14:31 ` Jun. T
2022-04-26 15:15 ` Peter Stephenson
2022-04-27 0:55 ` Bart Schaefer
2022-04-27 9:16 ` Jun T
2022-04-27 0:38 ` Bart Schaefer
2022-04-27 9:34 ` Peter Stephenson
2022-04-27 10:28 ` Jun T
2022-04-27 12:42 ` Jun T
2022-04-27 13:58 ` Jun T
2022-04-27 15:25 ` Bart Schaefer
2022-04-27 16:18 ` Jun. T [this message]
2022-04-27 19:54 ` Jordan Patterson
2022-04-28 9:53 ` Jun T
2022-04-28 14:56 ` Bart Schaefer
2022-04-28 18:51 ` Jun. T
2022-04-29 0:28 ` Bart Schaefer
2022-04-29 2:25 ` Jun. T
2022-04-26 1:08 ` Bart Schaefer
2022-04-26 3:03 ` Jordan Patterson
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