[OE-core] [PATCH 1/1] sstate.bbclass: fix parallel building issue
Rongqing Li
rongqing.li at windriver.com
Fri Aug 16 09:05:28 UTC 2013
On 08/16/2013 04:25 PM, Rongqing Li wrote:
>>> Do we need some kind of a read/write lock on accessing those files.
>>> (Is this
>>> even something that we can do easily though the existing mechanisms?)
>>
>> It would kill performance for no good reason, been there, looked at
>> it...
>>
>> Cheers,
>>
>> Richard
>>
>
> I think reverting the below optimization maybe better than using lock
>
> commit 8c5544c2311b080bb212efb7f6b804db63e125f5
> Author: Richard Purdie <richard.purdie at linuxfoundation.org>
> Date: Thu Oct 11 13:36:53 2012 +0100
>
> scripts/cp-noerror: Try and use hardlinks if possible
>
> Since we generally have lots of copies of the directories created
> using this tool, use
> hardlinks where possible. This should save a little disk space and
> improve performance
> slightly.
>
> (From OE-Core rev: bfa11c028c2da093f7b4e6b7b1d611da90ae052f)
>
> Signed-off-by: Richard Purdie <richard.purdie at linuxfoundation.org>
>
>
> -Roy
>
>
I think the upper commit saves lots of space, but the saved time maybe
be ignored.
On my general building image.
1. aclocal size and numbers of files
bitbake_build/tmp/sysroots/x86_64-linux/usr/share$ du -sh aclocal
768K aclocal
bitbake_build/tmp/sysroots/x86_64-linux/usr/share$ ls aclocal|wc
54 54 621
2. do hardlink copy 1000 times
bitbake_build/tmp/sysroots/x86_64-linux/usr/share$ cat ./aa
#! /bin/bash
n=0
while [ $n -le 1000 ] ; do
n=`expr "$n" + 1`
cp -alf aclocal ./tmp/
rm -rf ./tmp/aclocal
done
/bitbake_build/tmp/sysroots/x86_64-linux/usr/share$ time ./aa
real 0m4.416s
user 0m0.084s
sys 0m0.256s
2. do copy 1000 times
bitbake_build/tmp/sysroots/x86_64-linux/usr/share$ cat ./aa
#! /bin/bash
n=0
while [ $n -le 1000 ] ; do
n=`expr "$n" + 1`
cp -rf aclocal ./tmp/
rm -rf ./tmp/aclocal
done
bitbake_build/tmp/sysroots/x86_64-linux/usr/share$ time ./aa
real 0m8.707s
user 0m0.104s
sys 0m0.324s
Since we need several hours to compile a image, several seconds
improvement...
--
Best Reagrds,
Roy | RongQing Li
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