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* What are thoses [btrfs-cache-nnn] kernel threads ?
@ 2011-05-19  2:37 Christian Robert
  2011-05-19 18:26 ` Josef Bacik
  0 siblings, 1 reply; 6+ messages in thread
From: Christian Robert @ 2011-05-19  2:37 UTC (permalink / raw)
  To: linux-btrfs

hi,

 everyday at around 17:00, but today at 18:38 I start
 a multithread job (a la make -j4) who rsync
 257 huge directory from a remote host to my
 machine (at kernel 2.6.39-rc7 since yesterday)

below is the load average on the machine

2011-05-18 18:36 -> 0.00 0.11 0.13 1/218 1923
2011-05-18 18:37 -> 0.00 0.09 0.13 1/218 1923
2011-05-18 18:38 -> 0.42 0.17 0.15 1/240 2275  <- job started here
2011-05-18 18:39 -> 0.62 0.26 0.18 1/243 2287
2011-05-18 18:40 -> 1.78 0.64 0.32 1/244 2288
2011-05-18 18:41 -> 1.45 0.76 0.38 1/244 2297
2011-05-18 18:42 -> 1.94 1.02 0.49 1/244 2310
2011-05-18 18:43 -> 2.27 1.28 0.62 1/242 2325
2011-05-18 18:44 -> 2.39 1.45 0.71 1/247 2333
2011-05-18 18:45 -> 2.39 1.61 0.81 1/246 2359
2011-05-18 18:46 -> 3.22 1.95 0.98 1/248 2375
2011-05-18 18:47 -> 3.16 2.17 1.12 1/247 2386
2011-05-18 18:48 -> 3.40 2.39 1.25 1/249 2394
2011-05-18 18:49 -> 4.33 2.82 1.47 1/249 2395
2011-05-18 18:50 -> 3.93 3.01 1.63 1/246 2406
2011-05-18 18:51 -> 3.81 3.14 1.75 1/248 2410
2011-05-18 18:52 -> 3.92 3.32 1.90 1/247 2417
2011-05-18 18:53 -> 2.62 3.06 1.90 1/246 2431
2011-05-18 18:54 -> 3.52 3.22 2.03 1/248 2433
2011-05-18 18:55 -> 3.84 3.38 2.16 1/247 2439
2011-05-18 18:56 -> 2.91 3.26 2.20 1/245 2450
2011-05-18 18:57 -> 2.75 3.11 2.22 1/248 2457
2011-05-18 18:58 -> 3.59 3.29 2.33 1/248 2458
2011-05-18 18:59 -> 3.41 3.30 2.40 1/248 2468
2011-05-18 19:00 -> 3.76 3.40 2.49 1/247 2477
2011-05-18 19:01 -> 4.28 3.60 2.61 1/248 2488
2011-05-18 19:02 -> 4.06 3.67 2.70 1/247 2502
2011-05-18 19:03 -> 2.16 3.21 2.60 1/244 2515
2011-05-18 19:04 -> 2.81 3.17 2.62 1/247 2518
2011-05-18 19:05 -> 3.23 3.24 2.68 1/246 2522
2011-05-18 19:06 -> 3.53 3.32 2.74 1/246 2544
2011-05-18 19:07 -> 2.89 3.13 2.71 1/245 2550
2011-05-18 19:08 -> 3.68 3.28 2.79 1/247 2557
2011-05-18 19:09 -> 4.47 3.62 2.94 2/242 2571
2011-05-18 19:10 -> 3.20 3.39 2.90 1/244 2577
2011-05-18 19:11 -> 5.35 4.03 3.16 1/244 2584
2011-05-18 19:12 -> 5.07 4.20 3.26 3/245 2588
2011-05-18 19:13 -> 2.69 3.72 3.16 1/241 2602
2011-05-18 19:14 -> 3.37 3.70 3.19 1/244 2605
2011-05-18 19:15 -> 3.55 3.71 3.22 1/242 2611
2011-05-18 19:16 -> 2.94 3.48 3.18 1/243 2621
2011-05-18 19:17 -> 3.15 3.45 3.19 1/241 2630
2011-05-18 19:18 -> 3.02 3.37 3.17 1/242 2639
2011-05-18 19:19 -> 3.47 3.40 3.19 1/243 2649
2011-05-18 19:20 -> 3.71 3.46 3.23 1/243 2650
2011-05-18 19:21 -> 2.64 3.22 3.16 1/241 2664
2011-05-18 19:22 -> 3.48 3.31 3.19 1/244 2671
2011-05-18 19:23 -> 4.57 3.63 3.31 1/243 2675
2011-05-18 19:24 -> 4.06 3.66 3.34 1/242 2684
2011-05-18 19:25 -> 5.34 4.06 3.49 1/250 2699
2011-05-18 19:26 -> 6.18 4.57 3.71 1/244 2707
2011-05-18 19:27 -> 5.21 4.54 3.75 1/244 2711
2011-05-18 19:28 -> 4.17 4.37 3.74 1/244 2721
2011-05-18 19:29 -> 4.14 4.34 3.77 1/243 2728
2011-05-18 19:30 -> 4.52 4.40 3.82 1/243 2734
2011-05-18 19:31 -> 4.74 4.50 3.90 1/244 2743
2011-05-18 19:32 -> 5.09 4.60 3.97 3/244 2754
2011-05-18 19:33 -> 4.59 4.60 4.01 1/242 2765
2011-05-18 19:34 -> 4.39 4.53 4.02 1/243 2769
2011-05-18 19:35 -> 4.75 4.60 4.08 1/243 2773
2011-05-18 19:36 -> 4.98 4.66 4.13 2/245 2783
2011-05-18 19:37 -> 4.29 4.55 4.13 1/245 2797
2011-05-18 19:38 -> 7.16 5.27 4.39 1/243 2809
2011-05-18 19:39 -> 6.31 5.31 4.46 1/247 2815
2011-05-18 19:40 -> 6.29 5.40 4.54 1/251 2827
2011-05-18 19:41 -> 6.31 5.66 4.69 2/245 2838
2011-05-18 19:42 -> 4.43 5.25 4.61 1/243 2848
2011-05-18 19:43 -> 5.13 5.30 4.67 1/247 2856
2011-05-18 19:44 -> 5.39 5.31 4.71 1/243 2866
2011-05-18 19:45 -> 3.95 4.94 4.62 2/242 2874
2011-05-18 19:46 -> 4.59 4.99 4.66 1/243 2884
2011-05-18 19:47 -> 4.97 5.06 4.71 1/243 2889
2011-05-18 19:48 -> 5.51 5.25 4.79 1/245 2899
2011-05-18 19:49 -> 5.19 5.22 4.82 1/242 2905
2011-05-18 19:50 -> 5.21 5.18 4.82 2/246 2911
2011-05-18 19:51 -> 6.80 5.55 4.97 1/248 2918
2011-05-18 19:52 -> 6.11 5.67 5.05 1/241 2924
2011-05-18 19:53 -> 5.89 5.72 5.11 3/240 2938
2011-05-18 19:54 -> 3.96 5.20 4.96 1/241 2944
2011-05-18 19:55 -> 5.03 5.32 5.02 1/244 2952
2011-05-18 19:56 -> 4.81 5.22 5.01 1/243 2954
2011-05-18 19:57 -> 5.01 5.22 5.03 1/242 2958
2011-05-18 19:58 -> 4.82 5.15 5.02 1/242 2965
2011-05-18 19:59 -> 4.37 4.99 4.98 1/241 2978
2011-05-18 20:00 -> 4.93 4.98 4.97 3/243 2985
2011-05-18 20:01 -> 4.56 4.85 4.93 1/243 2995
2011-05-18 20:02 -> 4.41 4.76 4.89 2/243 3012
2011-05-18 20:03 -> 4.06 4.59 4.82 2/245 3022
2011-05-18 20:04 -> 3.94 4.47 4.77 2/243 3029
2011-05-18 20:05 -> 4.85 4.60 4.79 1/243 3034
2011-05-18 20:06 -> 4.90 4.71 4.82 1/242 3047
2011-05-18 20:07 -> 4.50 4.61 4.78 2/244 3055
2011-05-18 20:08 -> 4.06 4.48 4.72 2/245 3061
2011-05-18 20:09 -> 4.34 4.52 4.72 1/242 3070
2011-05-18 20:10 -> 4.95 4.63 4.75 1/246 3077
2011-05-18 20:11 -> 4.27 4.55 4.72 1/241 3089
2011-05-18 20:12 -> 4.44 4.58 4.72 1/241 3098
2011-05-18 20:13 -> 5.13 4.77 4.78 1/242 3104
2011-05-18 20:14 -> 4.20 4.56 4.70 1/245 3118
2011-05-18 20:15 -> 4.20 4.51 4.68 1/241 3128
2011-05-18 20:16 -> 4.43 4.52 4.67 1/244 3137
2011-05-18 20:17 -> 4.96 4.71 4.73 1/244 3146
2011-05-18 20:18 -> 5.36 4.85 4.78 3/246 3151
2011-05-18 20:19 -> 4.25 4.65 4.72 1/245 3165
2011-05-18 20:20 -> 4.75 4.77 4.76 1/243 3173
2011-05-18 20:21 -> 5.42 4.94 4.81 1/241 3187
2011-05-18 20:22 -> 3.58 4.49 4.67 3/243 3196
2011-05-18 20:23 -> 4.27 4.54 4.67 1/243 3199
2011-05-18 20:24 -> 4.26 4.53 4.67 1/243 3212
2011-05-18 20:25 -> 4.68 4.59 4.68 1/244 3224
2011-05-18 20:26 -> 4.50 4.59 4.68 1/242 3231
2011-05-18 20:27 -> 5.09 4.74 4.72 1/243 3243
2011-05-18 20:28 -> 5.09 4.76 4.72 1/246 3256
2011-05-18 20:29 -> 5.30 4.87 4.76 1/243 3260
2011-05-18 20:30 -> 6.75 5.37 4.94 1/244 3270
2011-05-18 20:31 -> 8.16 5.93 5.16 1/247 3286
2011-05-18 20:32 -> 8.30 6.34 5.34 2/242 3302
2011-05-18 20:33 -> 5.72 5.95 5.27 1/242 3303
2011-05-18 20:34 -> 3.55 5.33 5.10 2/240 3313
2011-05-18 20:35 -> 3.39 4.93 4.98 1/241 3322
2011-05-18 20:36 -> 3.59 4.69 4.89 1/242 3323
2011-05-18 20:37 -> 2.67 4.24 4.72 1/242 3335
2011-05-18 20:38 -> 3.42 4.18 4.67 1/241 3338
2011-05-18 20:39 -> 2.92 3.91 4.55 2/241 3346
2011-05-18 20:40 -> 3.23 3.80 4.47 1/242 3351
2011-05-18 20:41 -> 4.63 4.12 4.54 1/240 3361
2011-05-18 20:42 -> 5.07 4.33 4.59 1/242 3370
2011-05-18 20:43 -> 4.46 4.31 4.57 1/241 3376
2011-05-18 20:44 -> 5.27 4.52 4.62 2/246 3382
2011-05-18 20:45 -> 4.89 4.56 4.63 1/240 3396
2011-05-18 20:46 -> 4.83 4.55 4.62 2/242 3406
2011-05-18 20:47 -> 4.75 4.58 4.62 1/243 3410
2011-05-18 20:48 -> 5.25 4.75 4.68 1/243 3417
2011-05-18 20:49 -> 4.40 4.65 4.65 9/243 3429
2011-05-18 20:50 -> 5.32 4.87 4.73 3/242 3437
2011-05-18 20:51 -> 5.48 4.99 4.78 1/243 3443
2011-05-18 20:52 -> 5.81 5.24 4.88 2/244 3457
2011-05-18 20:53 -> 5.37 5.24 4.90 1/245 3464
2011-05-18 20:54 -> 7.99 5.93 5.16 1/252 3478
2011-05-18 20:55 -> 7.36 6.24 5.32 1/245 3488
2011-05-18 20:56 -> 5.82 6.04 5.31 1/245 3500
2011-05-18 20:57 -> 5.21 5.83 5.28 1/246 3505
2011-05-18 20:58 -> 4.93 5.67 5.27 1/242 3505
2011-05-18 20:59 -> 5.36 5.74 5.32 1/240 3521
2011-05-18 21:00 -> 4.47 5.30 5.19 1/250 3537
2011-05-18 21:01 -> 7.26 6.10 5.48 2/244 3546
2011-05-18 21:02 -> 8.85 6.61 5.69 3/252 3566
2011-05-18 21:03 -> 7.53 6.64 5.76 1/243 3573
2011-05-18 21:04 -> 5.49 6.27 5.69 2/240 3584
2011-05-18 21:05 -> 6.65 6.40 5.77 1/243 3595
2011-05-18 21:06 -> 5.56 6.12 5.71 2/244 3600
2011-05-18 21:07 -> 6.28 6.23 5.78 3/242 3612
2011-05-18 21:08 -> 5.31 5.90 5.69 2/242 3625
2011-05-18 21:09 -> 5.84 5.98 5.73 2/244 3633
2011-05-18 21:10 -> 6.69 6.27 5.85 4/244 3648
2011-05-18 21:11 -> 9.35 6.96 6.10 1/246 3662
2011-05-18 21:12 -> 7.45 6.78 6.09 1/244 3671
2011-05-18 21:13 -> 8.69 7.14 6.25 1/251 3707
2011-05-18 21:14 -> 10.05 7.68 6.48 1/251 3732

here I received an email notification that the loadavg exceeded 10


2011-05-18 21:15 -> 6.69 7.16 6.38 1/248 3748
2011-05-18 21:16 -> 7.44 7.26 6.46 1/252 3762
2011-05-18 21:17 -> 8.09 7.67 6.67 1/244 3777
2011-05-18 21:18 -> 9.36 8.05 6.86 1/248 3808
2011-05-18 21:19 -> 6.53 7.48 6.74 2/246 3821
2011-05-18 21:20 -> 9.34 8.11 7.00 1/243 3848
2011-05-18 21:21 -> 7.57 7.73 6.93 1/245 3861
2011-05-18 21:22 -> 6.52 7.47 6.90 1/248 3883
2011-05-18 21:23 -> 8.71 7.82 7.05 3/254 3901
2011-05-18 21:24 -> 9.72 8.21 7.23 2/253 3918
2011-05-18 21:25 -> 9.95 8.46 7.37 1/252 3929
2011-05-18 21:26 -> 10.77 8.81 7.55 1/253 3939
2011-05-18 21:27 -> 10.62 9.08 7.72 1/253 3967
2011-05-18 21:28 -> 8.49 8.71 7.67 1/251 3985
2011-05-18 21:29 -> 9.76 8.89 7.79 12/256 3999
2011-05-18 21:30 -> 10.17 9.44 8.07 1/244 4012
2011-05-18 21:31 -> 8.35 8.96 7.98 1/255 4039
2011-05-18 21:32 -> 8.95 9.20 8.14 2/245 4045
2011-05-18 21:33 -> 8.63 9.20 8.21 1/244 4053
2011-05-18 21:34 -> 8.72 9.24 8.29 1/248 4075
2011-05-18 21:35 -> 10.09 9.48 8.43 1/253 4124
2011-05-18 21:36 -> 12.77 10.16 8.72 1/257 4170
2011-05-18 21:37 -> 8.47 9.39 8.55 1/251 4198
2011-05-18 21:38 -> 8.81 9.35 8.59 1/252 4211
2011-05-18 21:39 -> 8.14 9.09 8.55 2/246 4240
2011-05-18 21:40 -> 13.65 10.34 9.00 1/256 4276
2011-05-18 21:41 -> 9.54 9.66 8.85 2/252 4335
2011-05-18 21:42 -> 13.92 10.82 9.29 1/253 4369
2011-05-18 21:43 -> 9.13 10.16 9.17 1/241 4389
2011-05-18 21:44 -> 9.47 9.91 9.14 1/249 4431
2011-05-18 21:45 -> 10.61 10.07 9.24 1/257 4451
2011-05-18 21:46 -> 11.34 10.56 9.47 1/244 4456

Here I killed -stop the 4 rsync process

2011-05-18 21:47 -> 5.10 8.96 8.99 1/234 4456
2011-05-18 21:48 -> 1.94 7.35 8.44 2/243 4484

Here I killed -cont the 4 rsync process

2011-05-18 21:49 -> 2.43 6.44 8.05 1/246 4488
2011-05-18 21:50 -> 3.50 6.01 7.80 1/246 4488
2011-05-18 21:51 -> 3.18 5.49 7.51 8/243 4498
2011-05-18 21:52 -> 3.50 5.15 7.27 1/244 4503
2011-05-18 21:53 -> 3.83 4.93 7.06 1/245 4504
2011-05-18 21:54 -> 3.02 4.52 6.79 1/243 4514
2011-05-18 21:55 -> 3.37 4.32 6.57 2/245 4520
2011-05-18 21:56 -> 3.51 4.17 6.38 2/245 4524
2011-05-18 21:57 -> 3.15 3.97 6.17 1/243 4542
2011-05-18 21:58 -> 3.67 3.96 6.03 2/244 4543
2011-05-18 21:59 -> 3.55 3.88 5.87 1/243 4558
2011-05-18 22:00 -> 2.88 3.60 5.65 1/244 4563
2011-05-18 22:01 -> 3.29 3.62 5.53 1/245 4568
2011-05-18 22:02 -> 3.53 3.63 5.42 3/247 4582
2011-05-18 22:03 -> 3.17 3.54 5.27 2/244 4592
2011-05-18 22:04 -> 3.27 3.45 5.13 1/246 4598
2011-05-18 22:05 -> 3.64 3.53 5.06 1/245 4601
2011-05-18 22:06 -> 2.68 3.28 4.88 2/244 4612
2011-05-18 22:07 -> 3.25 3.33 4.79 1/245 4614
2011-05-18 22:08 -> 3.95 3.51 4.76 1/246 4615
2011-05-18 22:09 -> 3.23 3.43 4.66 1/242 4624
2011-05-18 22:10 -> 3.08 3.34 4.55 1/245 4631
2011-05-18 22:11 -> 3.46 3.43 4.51 1/244 4643
2011-05-18 22:12 -> 3.90 3.55 4.48 1/243 4658

a "top" when at loadavg 10+ show something like 8 or 10
kernel threads named btrfs-cache-*  all in "D" status.

I'm no expert at all but I think thoses kthreads
lack a bit of priority to finish the job they have to
do. I will let you judge on that.

I've seen that behavior with older kernels too (plain fedora-14)

It does not happen often, may be one time every few weeks.
When it happen, the loadavg increase endlessly until all the
rsync prosess finish. Then loadavg drop to zero.


Christian Robert,
Poly.

^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2011-05-20 12:11 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2011-05-19  2:37 What are thoses [btrfs-cache-nnn] kernel threads ? Christian Robert
2011-05-19 18:26 ` Josef Bacik
2011-05-20  3:13   ` Miguel Garrido
2011-05-20  5:32     ` Chester
2011-05-20 11:22       ` Chris Mason
2011-05-20 12:11         ` Miguel Garrido

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