linux-kernel - Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression

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Date:	Thu, 11 Aug 2016 13:05:35 +1000
From:	Dave Chinner <david@...morbit.com>
To:	Ye Xiaolong <xiaolong.ye@...el.com>
Cc:	"Huang, Ying" <ying.huang@...el.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Bob Peterson <rpeterso@...hat.com>,
	Wu Fengguang <fengguang.wu@...el.com>, LKP <lkp@...org>,
	Christoph Hellwig <hch@....de>
Subject: Re: [LKP] [lkp] [xfs] 68a9f5e700: aim7.jobs-per-min -13.6% regression

On Thu, Aug 11, 2016 at 10:36:59AM +0800, Ye Xiaolong wrote:
> On 08/11, Dave Chinner wrote:
> >On Thu, Aug 11, 2016 at 11:16:12AM +1000, Dave Chinner wrote:
> >> I need to see these events:
> >> 
> >> 	xfs_file*
> >> 	xfs_iomap*
> >> 	xfs_get_block*
> >> 
> >> For both kernels. An example trace from 4.8-rc1 running the command
> >> `xfs_io -f -c 'pwrite 0 512k -b 128k' /mnt/scratch/fooey doing an
> >> overwrite and extend of the existing file ends up looking like:
> >> 
> >> $ sudo trace-cmd start -e xfs_iomap\* -e xfs_file\* -e xfs_get_blocks\*
> >> $ sudo cat /sys/kernel/tracing/trace_pipe
> >>            <...>-2946  [001] .... 253971.750304: xfs_file_ioctl: dev 253:32 ino 0x84
> >>           xfs_io-2946  [001] .... 253971.750938: xfs_file_buffered_write: dev 253:32 ino 0x84 size 0x40000 offset 0x0 count 0x20000
> >>           xfs_io-2946  [001] .... 253971.750961: xfs_iomap_found: dev 253:32 ino 0x84 size 0x40000 offset 0x0 count 131072 type invalid startoff 0x0 startblock 24 blockcount 0x60
> >>           xfs_io-2946  [001] .... 253971.751114: xfs_file_buffered_write: dev 253:32 ino 0x84 size 0x40000 offset 0x20000 count 0x20000
> >>           xfs_io-2946  [001] .... 253971.751128: xfs_iomap_found: dev 253:32 ino 0x84 size 0x40000 offset 0x20000 count 131072 type invalid startoff 0x0 startblock 24 blockcount 0x60
> >>           xfs_io-2946  [001] .... 253971.751234: xfs_file_buffered_write: dev 253:32 ino 0x84 size 0x40000 offset 0x40000 count 0x20000
> >>           xfs_io-2946  [001] .... 253971.751236: xfs_iomap_found: dev 253:32 ino 0x84 size 0x40000 offset 0x40000 count 131072 type invalid startoff 0x0 startblock 24 blockcount 0x60
> >>           xfs_io-2946  [001] .... 253971.751381: xfs_file_buffered_write: dev 253:32 ino 0x84 size 0x40000 offset 0x60000 count 0x20000
> >>           xfs_io-2946  [001] .... 253971.751415: xfs_iomap_prealloc_size: dev 253:32 ino 0x84 prealloc blocks 128 shift 0 m_writeio_blocks 16
> >>           xfs_io-2946  [001] .... 253971.751425: xfs_iomap_alloc: dev 253:32 ino 0x84 size 0x40000 offset 0x60000 count 131072 type invalid startoff 0x60 startblock -1 blockcount 0x90
> >> 
> >> That's the output I need for the complete test - you'll need to use
> >> a better recording mechanism that this (e.g. trace-cmd record,
> >> trace-cmd report) because it will generate a lot of events. Compress
> >> the two report files (they'll be large) and send them to me offlist.
> >
> >Can you also send me the output of xfs_info on the filesystem you
> >are testing?
> 
> Hi, Dave
> 
> Here is the xfs_info output:
> 
> # xfs_info /fs/ram0/
> meta-data=/dev/ram0              isize=256    agcount=4, agsize=3145728 blks
>          =                       sectsz=4096  attr=2, projid32bit=1
>          =                       crc=0        finobt=0
> data     =                       bsize=4096   blocks=12582912, imaxpct=25
>          =                       sunit=0      swidth=0 blks
> naming   =version 2              bsize=4096   ascii-ci=0 ftype=0
> log      =internal               bsize=4096   blocks=6144, version=2
>          =                       sectsz=4096  sunit=1 blks, lazy-count=1
> realtime =none                   extsz=4096   blocks=0, rtextents=0

OK, nothing unusual there. One thing that I did just think of - how
close to ENOSPC does this test get? i.e. are we hitting the "we're
almost out of free space" slow paths on this test?

Cheers,

dave.
> 
> Thanks,
> Xiaolong
> >
> >Cheers,
> >
> >Dave.
> >-- 
> >Dave Chinner
> >david@...morbit.com
> >_______________________________________________
> >LKP mailing list
> >LKP@...ts.01.org
> >https://lists.01.org/mailman/listinfo/lkp
> 

-- 
Dave Chinner
david@...morbit.com

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