> From: Dexuan Cui > Sent: Thursday, September 24, 2015 8:16 > To: 'Tejun Heo' <[email protected]>; Chris Mason <[email protected]>; Theodore Ts'o > <[email protected]>; Andreas Dilger <[email protected]>; linux- > [email protected]; [email protected]; linux- > [email protected] > Subject: RE: ext4: performance regression introduced by the cgroup writeback > support > > > -----Original Message----- > > From: Tejun Heo [mailto:[email protected]] On Behalf Of Tejun Heo > > Sent: Thursday, September 24, 2015 2:54 > > To: Chris Mason <[email protected]>; Dexuan Cui <[email protected]>; > > Theodore Ts'o <[email protected]>; Andreas Dilger <[email protected]>; > > [email protected]; [email protected]; linux- > > [email protected] > > 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
Hi Tejun, Thank you! I believe your patch fixes my issue, according to my test. -- Dexuan -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
