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From: Baruch Siach <baruch@tkos.co.il>
To: buildroot@busybox.net
Subject: [Buildroot] [PATCHv2 7/7] automatically set PARALLEL_JOBS when BR2_JLEVEL is 0
Date: Thu, 14 Jun 2012 21:09:18 +0300	[thread overview]
Message-ID: <20120614180918.GA8258@tarshish> (raw)
In-Reply-To: <1339686165-10145-1-git-send-email-ntl@pobox.com>

Hi Nathan,

On Thu, Jun 14, 2012 at 10:02:45AM -0500, Nathan Lynch wrote:
> When BR2_JLEVEL is 0, set PARALLEL_JOBS to double the number of CPUs
> detected.  This allows one to more or less fully utilize the host
> system without manually tuning the configuration.
> 
> Also make 0 the default value for BR2_JLEVEL.
> 
> Signed-off-by: Nathan Lynch <ntl@pobox.com>
> ---

[snip]

> +ifeq ($(BR2_JLEVEL),0)
> +PARALLEL_JOBS:=$(shell echo \
> +	$$((2 * `getconf _NPROCESSORS_ONLN 2>/dev/null || echo 1`)))
> +else
>  PARALLEL_JOBS:=$(BR2_JLEVEL)
> +endif

IMO, there should be a comment here explaining the magic (2*CPUs) number.

baruch

-- 
     http://baruch.siach.name/blog/                  ~. .~   Tk Open Systems
=}------------------------------------------------ooO--U--Ooo------------{=
   - baruch at tkos.co.il - tel: +972.2.679.5364, http://www.tkos.co.il -

  reply	other threads:[~2012-06-14 18:09 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-06-12  2:09 [Buildroot] [PATCH 0/7] automatically determine job concurrency Nathan Lynch
2012-06-12  2:09 ` [Buildroot] [PATCH 1/7] introduce PARALLEL_JOBS build system variable Nathan Lynch
2012-06-12  2:09 ` [Buildroot] [PATCH 2/7] boost: change uses of BR2_JLEVEL to PARALLEL_JOBS Nathan Lynch
2012-06-12  2:09 ` [Buildroot] [PATCH 3/7] cmake: change use " Nathan Lynch
2012-06-12  2:09 ` [Buildroot] [PATCH 4/7] midori: " Nathan Lynch
2012-06-12  2:09 ` [Buildroot] [PATCH 5/7] qt: " Nathan Lynch
2012-06-12  2:09 ` [Buildroot] [PATCH 6/7] toolchain/crosstool-ng: " Nathan Lynch
2012-06-12  2:09 ` [Buildroot] [PATCH 7/7] automatically set PARALLEL_JOBS when BR2_JLEVEL is 0 Nathan Lynch
2012-06-13 23:27   ` Arnout Vandecappelle
2012-06-13 23:44     ` Nathan Lynch
2012-06-14  6:07       ` Peter Korsgaard
2012-06-14  6:16         ` Nathan Lynch
2012-06-14  8:56           ` Peter Korsgaard
2012-06-14  8:33     ` Richard Braun
2012-06-14 15:02   ` [Buildroot] [PATCHv2 " Nathan Lynch
2012-06-14 18:09     ` Baruch Siach [this message]
2012-06-16 19:37   ` [Buildroot] [PATCHv3 " Nathan Lynch
2012-06-24  9:13 ` [Buildroot] [PATCH 0/7] automatically determine job concurrency Peter Korsgaard

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