From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <e@80x24.org>
X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on dcvr.yhbt.net
X-Spam-Level: 
X-Spam-ASN:  
X-Spam-Status: No, score=-4.0 required=3.0 tests=ALL_TRUSTED,BAYES_00
	shortcircuit=no autolearn=ham autolearn_force=no version=3.4.0
Received: from localhost (dcvr.yhbt.net [127.0.0.1])
	by dcvr.yhbt.net (Postfix) with ESMTP id AE66B202A5
	for <spew@80x24.org>; Tue, 26 Sep 2017 00:55:09 +0000 (UTC)
Date: Tue, 26 Sep 2017 00:55:09 +0000
From: Eric Wong <e@80x24.org>
To: spew@80x24.org
Subject: Re: [PATCH 0/3] implement IO.writev method
Message-ID: <20170926005509.GA22313@starla>
References: <1268452495-26406-1-git-send-email-normalperson@yhbt.net>
 <1268452495-26406-2-git-send-email-normalperson@yhbt.net>
 <20100313040220.GA26654@dcvr.yhbt.net>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
In-Reply-To: <20100313040220.GA26654@dcvr.yhbt.net>
List-Id: <spew.80x24.org>

> The following series implements IO.writev as a wrapper for the
> writev(2) system call.
> 
> IO.writev can be used to efficiently write an array of strings
> atomically without the need to create a temporary string via Array#join
> or repeatedly make expensive method/system calls.
> 
> Benchmark results (see script below):
> 
>   Rehearsal --------------------------------------------
>   syswrite  16.950000   2.010000  18.960000 ( 19.023356)
>   writev     7.420000   2.480000   9.900000 (  9.903122)
>   ---------------------------------- total: 28.860000sec
>                  
>                  user     system      total        real
>   syswrite  16.930000   1.940000  18.870000 ( 18.906436)
>   writev     7.120000   2.760000   9.880000 (  9.905839)
> 
> If everything looks OK, you may pull here:
>   git://git.bogomips.org/io-extra.git
> 
> or browse cgit here:
>   http://git.bogomips.org/cgit/io-extra.git
> 
> ----------------------------- 8< ------------------------------
> # -*- encoding: binary -*-
> require 'benchmark'
> require 'io/extra'
> 
> # writev wins by larger margins as buffers get larger or iovcnt increases
> nr = 10000000
> buf = '.' * 25
> iovcnt = 3
> vec = iovcnt.times.map { buf }
> 
> null = File.open("/dev/null", "wb")
> null.sync = true
> Benchmark.bmbm do |x|
>   x.report("syswrite") do
>     nr.times { null.syswrite(vec.join("")) }
>   end
>   x.report("writev") do
>     nr.times { IO.writev(null.fileno, vec) }
>   end
> end
> ----------------------------- 8< ------------------------------