lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <08750e508f1643b2a2c0bb495c91d450@SIXPR30MB031.064d.mgd.msft.net>
Date:	Thu, 24 Sep 2015 00:15:37 +0000
From:	Dexuan Cui <decui@...rosoft.com>
To:	Tejun Heo <tj@...nel.org>, Chris Mason <clm@...com>,
	Theodore Ts'o <tytso@....edu>,
	Andreas Dilger <adilger.kernel@...ger.ca>,
	"linux-ext4@...r.kernel.org" <linux-ext4@...r.kernel.org>,
	"linux-fsdevel@...r.kernel.org" <linux-fsdevel@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: ext4: performance regression introduced by the cgroup writeback
 support

> -----Original Message-----
> From: Tejun Heo [mailto:htejun@...il.com] On Behalf Of Tejun Heo
> Sent: Thursday, September 24, 2015 2:54
> To: Chris Mason <clm@...com>; Dexuan Cui <decui@...rosoft.com>;
> Theodore Ts'o <tytso@....edu>; Andreas Dilger <adilger.kernel@...ger.ca>;
> linux-ext4@...r.kernel.org; linux-fsdevel@...r.kernel.org; linux-
> kernel@...r.kernel.org
> Subject: Re: ext4: performance regression introduced by the cgroup writeback
> support
> 
> On Wed, Sep 23, 2015 at 12:13:59PM -0400, Chris Mason wrote:
> > > The issue is: under high CPU and disk I/O pressure, *some* processes can
> suffer from a very slow write speed (e.g., <1MB/s or even only 20KB/s), while
> the normal write speed should be at least dozens of MB/s.
> 
> So, I think I know what caused this regression.  Separate wb domains
> shouldn't have been enabled on traditional hierarchies.  It doesn't
> work there and leads to multiple wb domains competing on the same
> blkcg and the bw estimation would go completely haywire.  Will update
> soon.
> 
> Thanks.
> 
> --
> tejun

Thanks a lot for the quick fix, Tejun!

I'll test the fix.
I'll report back in case it can't fix the issue --I think this is unlikely. :-)

-- Dexuan
--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Powered by blists - more mailing lists