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From: Antoine Martin <antoine@nagafix.co.uk>
To: Michael Tokarev <mjt@tls.msk.ru>
Cc: kvm@vger.kernel.org
Subject: Re: repeatable hang with loop mount and heavy IO in guest [NOT SOLVED]
Date: Sat, 23 Jan 2010 02:15:36 +0700	[thread overview]
Message-ID: <4B59F958.8030709@nagafix.co.uk> (raw)
In-Reply-To: <4B59EE4E.6070005@nagafix.co.uk>

On 01/23/2010 01:28 AM, Antoine Martin wrote:
> On 01/22/2010 02:57 PM, Michael Tokarev wrote:
>> Antoine Martin wrote:
>>> I've tried various guests, including most recent Fedora12 kernels,
>>> custom 2.6.32.x
>>> All of them hang around the same point (~1GB written) when I do 
>>> heavy IO
>>> write inside the guest.
>> []
>>> Host is running: 2.6.31.4
>>> QEMU PC emulator version 0.10.50 (qemu-kvm-devel-88)
>> Please update to last version and repeat.  kvm-88 is ancient and
>> _lots_ of stuff fixed and changed since that time, I doubt anyone
>> here will try to dig into kvm-88 problems.
>>
>> Current kvm is qemu-kvm-0.12.2, released yesterday.
> Sorry about that, I didn't realize 88 was so far behind.
> Upgrading to qemu-kvm-0.12.2 did solve my IO problems.
Only for a while. Same problem just re-occurred, only this time it went 
a little further.
It is now just sitting there, with a load average of exactly 3.0 (+- 5%)

Here is a good trace of the symptom during writeback, you can see it 
write the data at around 50MB/s, it goes from being idle to sys, but 
after a while it just stops writing and goes into mostly wait state:
----total-cpu-usage---- -dsk/total- -net/total- ---paging-- ---system--
   1   0  99   0   0   0|   0     0 | 198B  614B|   0     0 |  36    17
   1   0  99   0   0   0|   0     0 | 198B  710B|   0     0 |  31    17
   1   1  98   0   0   0|   0   128k| 240B  720B|   0     0 |  39    26
   1   1  98   0   0   0|   0     0 | 132B  564B|   0     0 |  31    14
   1   0  99   0   0   0|   0     0 | 132B  468B|   0     0 |  31    14
   1   1  98   0   0   0|   0     0 |  66B  354B|   0     0 |  30    13
   0   4  11  85   0   0| 852k    0 | 444B 1194B|   0     0 | 215   477
   2   2   0  96   0   0| 500k    0 | 132B  756B|   0     0 | 169   458
   3  57   0  39   1   0| 228k   10M| 132B  692B|   0     0 | 476  5387
   6  94   0   0   0   0|  28k   23M| 132B  884B|   0     0 | 373  2142
   6  89   0   2   2   0|  40k   38M|  66B  692B|   0  8192B| 502  5651
   4  47   0  48   0   0| 140k   34M| 132B  836B|   0     0 | 605  1664
   3  64   0  30   2   0|  60k   50M| 132B  370B|   0    60k| 750   631
   4  59   0  35   2   0|  48k   45M| 132B  836B|   0    28k| 708  1293
   7  81   0  10   2   0|  68k   67M| 132B  788B|   0   124k| 928  1634
   5  74   0  20   1   0|  48k   48M| 132B  756B|   0   316k| 830  5715
   5  70   0  24   1   0| 168k   48M| 132B  676B|   0   100k| 734  5325
   4  70   0  24   1   0|  72k   49M| 132B  948B|   0    88k| 776  3784
   5  57   0  37   1   0|  36k   37M| 132B  996B|   0   480k| 602   369
   2  21   0  77   0   0|  36k   23M| 132B  724B|   0    72k| 318  1033
   4  51   0  43   2   0| 112k   43M| 132B  756B|   0   112k| 681   909
   5  55   0  40   0   0|  88k   48M| 140B  926B|  16k   12k| 698   557
----total-cpu-usage---- -dsk/total- -net/total- ---paging-- ---system--
usr sys idl wai hiq siq| read  writ| recv  send|  in   out | int   csw
   3  45   0  51   1   0|2248k   29M| 198B 1028B|  28k   44k| 681  5468
   1  21   0  78   0   0|  92k   17M|1275B 2049B|  92k   52k| 328  1883
   3  30   0  66   1   0| 288k   28M| 498B 2116B|   0    40k| 455   679
   1   1   0  98   0   0|4096B    0 | 394B 1340B|4096B    0 |  41    19
   1   1   0  98   0   0| 148k   52k| 881B 1592B|4096B   44k|  75    61
   1   2   0  97   0   0|1408k    0 | 351B 1727B|   0     0 | 110   109
   2   1   0  97   0   0|8192B    0 |1422B 1940B|   0     0 |  53    34
   1   0   0  99   0   0|4096B   12k| 328B 1018B|   0     0 |  41    24
   1   4   0  95   0   0| 340k    0 |3075B 2152B|4096B    0 | 153   191
   4   7   0  89   0   0|1004k   44k|1526B 1906B|   0     0 | 254   244
   0   1   0  99   0   0|  76k    0 | 708B 1708B|   0     0 |  67    57
   1   1   0  98   0   0|   0     0 | 174B  702B|   0     0 |  32    14
   1   1   0  98   0   0|   0     0 | 132B  354B|   0     0 |  32    11
   1   0   0  99   0   0|   0     0 | 132B  468B|   0     0 |  32    16
   1   0   0  99   0   0|   0     0 | 132B  468B|   0     0 |  32    14
   1   1   0  98   0   0|   0    52k| 132B  678B|   0     0 |  41    27
   1   0   0  99   0   0|   0     0 | 198B  678B|   0     0 |  35    17
   1   1   0  98   0   0|   0     0 | 198B  468B|   0     0 |  34    14
   1   0   0  99   0   0|   0     0 |  66B  354B|   0     0 |  28    11
   1   0   0  99   0   0|   0     0 |  66B  354B|   0     0 |  28     9
   1   1   0  98   0   0|   0     0 | 132B  468B|   0     0 |  34    16
   1   0   0  98   0   1|   0     0 |  66B  354B|   0     0 |  30    11
   1   1   0  98   0   0|   0     0 |  66B  354B|   0     0 |  29    11
 From that point onwards, nothing will happen.
The host has disk IO to spare... So what is it waiting for??

QEMU PC emulator version 0.12.2 (qemu-kvm-0.12.2), Copyright (c) 
2003-2008 Fabrice Bellard
Guests: various, all recent kernels.
Host: 2.6.31.4

Please advise.

Thanks
Antoine


  reply	other threads:[~2010-01-22 19:15 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-01-21 17:26 repeatable hang with loop mount and heavy IO in guest Antoine Martin
2010-01-21 20:08 ` RW
2010-01-21 21:08   ` Thomas Beinicke
2010-01-21 21:36     ` RW
2010-01-22  7:57 ` Michael Tokarev
2010-01-22 18:28   ` repeatable hang with loop mount and heavy IO in guest [SOLVED] Antoine Martin
2010-01-22 19:15     ` Antoine Martin [this message]
2010-01-24 11:23       ` repeatable hang with loop mount and heavy IO in guest [NOT SOLVED] Antoine Martin
2010-02-03 19:28       ` Antoine Martin
2010-02-26 17:38         ` repeatable hang with loop mount and heavy IO in guest Antoine Martin
2010-05-21  9:38           ` repeatable hang with loop mount and heavy IO in guest (now in host - not KVM then..) Antoine Martin
2010-05-22 18:10             ` Jim Paris
2010-05-22 19:33               ` Antoine Martin

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