Re: [PATCH 1/1] sstate.bbclass: fix parallel building issue

From: Rongqing Li <rongqing.li@windriver.com>
To: Richard Purdie <richard.purdie@linuxfoundation.org>
Cc: openembedded-core@lists.openembedded.org
Subject: Re: [PATCH 1/1] sstate.bbclass: fix parallel building issue
Date: Fri, 16 Aug 2013 16:25:02 +0800	[thread overview]
Message-ID: <520DE1DE.10608@windriver.com> (raw)
In-Reply-To: <1376607841.22952.103.camel@ted>


On 08/16/2013 07:04 AM, Richard Purdie wrote:
> On Thu, 2013-08-15 at 11:27 -0500, Mark Hatle wrote:
>> On 8/15/13 11:23 AM, Richard Purdie wrote:
>>> On Thu, 2013-08-15 at 10:55 +0100, Phil Blundell wrote:
>>>> On Thu, 2013-08-15 at 17:51 +0800, Rongqing Li wrote:
>>>>> OK, But your issue is not related to me.
>>>>>
>>>>> I can reproduce my issue by two simple script.
>>>>
>>>> If tar is deciding that the file has "changed" just because the link
>>>> count on the dentry has increased, that sounds like it is probably a bug
>>>> in tar and ought to be fixed there.
>>>>
>>>> That said, I can't immediately think why autotools_copy_aclocal couldn't
>>>> use a symlink rather than a hard link which would avoid this whole
>>>> problem.  If the file is in the sysroot then there should be no risk of
>>>> it going away underneath its user.
>>>
>>> Sadly this doesn't work. We block copy a set of .m4 files from the
>>> sysroot. We can be running do_configure of package A whilst package B is
>>> de-installed from the sysroot and this leads to files disappearing
>>> whilst they're being accessed. Its turned out to be a really awkward
>>> problem to fix.
>>
>> 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@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@linuxfoundation.org>


-Roy


> _______________________________________________
> Openembedded-core mailing list
> Openembedded-core@lists.openembedded.org
> http://lists.openembedded.org/mailman/listinfo/openembedded-core
>
>

-- 
Best Reagrds,
Roy | RongQing Li