Analysis of the mogilefsd busywait bug

[Nathan Schmidt]

After applying the patch David Weekly suggested in http:// 
lists.danga.com/pipermail/mogilefs/2007-February/000762.html we've  
not seen the high CPU usage problem after about a week of 5-20 writes/ 
sec.

2.6.19.1.pbwiki-grsec #1 SMP i686 GNU/Linux, IO::AIO v2.33,  
Danga::Socket v1.56

Regards,
-Nathan / PBwiki



On Feb 28, 2007, at 1:45 PM, Brad Fitzpatrick wrote:

> I'm still very eager to solve this, but I've been traveling for  
> past 2+
> weeks, away from primary dev environments.
>
> We need to solve this before we deploy this version of MogileFS  
> into LJ
> production, so don't worry -- it'll get fixed.  Hopefully this week.
>
> - Brad
>
>
> On Wed, 28 Feb 2007, Jared Klett wrote:
>
>> 	I hate to be the squeaky wheel, but I'm still seeing the
>> mogilefsd taking 100% CPU aka the "busywait" bug after updating to
>> svn748 (the latest as of today).
>>
>> 	I reinitialized my entire MogileFS environment, injected one
>> file, and mogilefsd on one of the two tracker servers started  
>> spinning
>> at 100% CPU.
>>
>> 	I provided some debug info in this thread:
>>
>> http://lists.danga.com/pipermail/mogilefs/2007-February/000792.html
>>
>> 	I checked lsof and strace output and it's pretty much the same
>> story I laid out in that post.
>>
>> 	is there any new info or resolution on this issue?
>>
>> cheers,
>>
>> - Jared
>>
>> -----Original Message-----
>> From: mogilefs-bounces at lists.danga.com
>> [mailto:mogilefs-bounces at lists.danga.com] On Behalf Of Brad  
>> Fitzpatrick
>> Sent: Wednesday, February 14, 2007 3:23 AM
>> To: David Weekly
>> Cc: nathan at pbwiki.com; mogilefs at lists.danga.com; Brett G. Durrett
>> Subject: Re: Analysis of the mogilefsd busywait bug
>>
>> Committed in svn740.
>>
>> On Tue, 13 Feb 2007, David Weekly wrote: