[lustre-discuss] [EXTERNAL] Re: No read throughput shown for the sequential read write Filebench workload

Md Hasanur Rashid mrashid2 at uncc.edu
Wed Oct 13 08:54:40 PDT 2021


Even with clearing the locks (clear all the LDLM locks on the client after
the sync and drop caches commands), the stats look just the same as before.

For extents_stats, the stats look like these:

llite.hasanfs-ffff882fdc929800.extents_stats=
snapshot_time:         1634138089.122870 (secs.usecs)
                               read       |                write
      extents            calls    % cum%  |          calls    % cum%
   0K -    4K :            450  100  100  |              0    0    0
   4K -    8K :              0    0  100  |              0    0    0
   8K -   16K :              0    0  100  |              0    0    0
  16K -   32K :              0    0  100  |              0    0    0
  32K -   64K :              0    0  100  |              0    0    0
  64K -  128K :              0    0  100  |              0    0    0
 128K -  256K :              0    0  100  |              0    0    0
 256K -  512K :              0    0  100  |              0    0    0
 512K - 1024K :              0    0  100  |              0    0    0
   1M -    2M :              0    0  100  |           1600   46   46
   2M -    4M :              0    0  100  |              0    0   46
   4M -    8M :              0    0  100  |              0    0   46
   8M -   16M :              0    0  100  |              0    0   46
  16M -   32M :              0    0  100  |           1826   53  100

If we take a look at the client-side rpc_stats following are observed:

osc.hasanfs-OST0000-osc-ffff882fdc929800.rpc_stats=
snapshot_time:         1634137979.38657 (secs.usecs)
read RPCs in flight:  0
write RPCs in flight: 0
pending write pages:  0
pending read pages:   0

			read			write
pages per rpc         rpcs   % cum % |       rpcs   % cum %
1:		         0   0   0   |          0   0   0
2:		         0   0   0   |          0   0   0
4:		         0   0   0   |          0   0   0
8:		         0   0   0   |          0   0   0
16:		         0   0   0   |          0   0   0
32:		         0   0   0   |          0   0   0
64:		         0   0   0   |          0   0   0
128:		         0   0   0   |          0   0   0
256:		         0   0   0   |       3648 100 100

			read			write
rpcs in flight        rpcs   % cum % |       rpcs   % cum %
0:		         0   0   0   |          0   0   0
1:		         0   0   0   |         47   1   1
2:		         0   0   0   |         47   1   2
3:		         0   0   0   |         48   1   3
4:		         0   0   0   |         49   1   5
5:		         0   0   0   |         50   1   6
6:		         0   0   0   |         59   1   8
7:		         0   0   0   |         55   1   9
8:		         0   0   0   |         68   1  11
9:		         0   0   0   |       2209  60  72
10:		         0   0   0   |       1015  27  99
11:		         0   0   0   |          1   0 100

			read			write
offset                rpcs   % cum % |       rpcs   % cum %
0:		         0   0   0   |         66   1   1
1:		         0   0   0   |          0   0   1
2:		         0   0   0   |          0   0   1
4:		         0   0   0   |          0   0   1
8:		         0   0   0   |          0   0   1
16:		         0   0   0   |          0   0   1
32:		         0   0   0   |          0   0   1
64:		         0   0   0   |          0   0   1
128:		         0   0   0   |          0   0   1
256:		         0   0   0   |         66   1   3
512:		         0   0   0   |        132   3   7
1024:		         0   0   0   |        264   7  14
2048:		         0   0   0   |        528  14  28
4096:		         0   0   0   |        864  23  52
8192:		         0   0   0   |       1728  47 100
osc.hasanfs-OST0001-osc-ffff882fdc929800.rpc_stats=
snapshot_time:         1634137979.39942 (secs.usecs)
read RPCs in flight:  0
write RPCs in flight: 0
pending write pages:  0
pending read pages:   0

			read			write
pages per rpc         rpcs   % cum % |       rpcs   % cum %
1:		        61  93  93   |          0   0   0
2:		         1   1  95   |          0   0   0
4:		         0   0  95   |          0   0   0
8:		         0   0  95   |          0   0   0
16:		         0   0  95   |          0   0   0
32:		         0   0  95   |          0   0   0
64:		         0   0  95   |          0   0   0
128:		         1   1  96   |          1   0   0
256:		         2   3 100   |       3792  99 100

			read			write
rpcs in flight        rpcs   % cum % |       rpcs   % cum %
0:		         0   0   0   |          0   0   0
1:		        63  96  96   |         45   1   1
2:		         2   3 100   |         45   1   2
3:		         0   0 100   |         45   1   3
4:		         0   0 100   |         45   1   4
5:		         0   0 100   |         45   1   5
6:		         0   0 100   |         49   1   7
7:		         0   0 100   |         47   1   8
8:		         0   0 100   |         57   1   9
9:		         0   0 100   |       2235  58  68
10:		         0   0 100   |       1180  31 100

			read			write
offset                rpcs   % cum % |       rpcs   % cum %
0:		         1   1   1   |         69   1   1
1:		         1   1   3   |          0   0   1
2:		         4   6   9   |          0   0   1
4:		         8  12  21   |          0   0   1
8:		        13  20  41   |          0   0   1
16:		        31  47  89   |          0   0   1
32:		         7  10 100   |          0   0   1
64:		         0   0 100   |          0   0   1
128:		         0   0 100   |          0   0   1
256:		         0   0 100   |         69   1   3
512:		         0   0 100   |        139   3   7
1024:		         0   0 100   |        276   7  14
2048:		         0   0 100   |        552  14  29
4096:		         0   0 100   |        896  23  52
8192:		         0   0 100   |       1792  47 100
osc.hasanfs-OST0002-osc-ffff882fdc929800.rpc_stats=
snapshot_time:         1634137979.41185 (secs.usecs)
read RPCs in flight:  0
write RPCs in flight: 0
pending write pages:  0
pending read pages:   0

			read			write
pages per rpc         rpcs   % cum % |       rpcs   % cum %
1:		         0   0   0   |          0   0   0
2:		         0   0   0   |          0   0   0
4:		         0   0   0   |          0   0   0
8:		         0   0   0   |          0   0   0
16:		         0   0   0   |          0   0   0
32:		         0   0   0   |          0   0   0
64:		         0   0   0   |          0   0   0
128:		         0   0   0   |          0   0   0
256:		         0   0   0   |       3776 100 100

			read			write
rpcs in flight        rpcs   % cum % |       rpcs   % cum %
0:		         0   0   0   |          0   0   0
1:		         0   0   0   |         43   1   1
2:		         0   0   0   |         45   1   2
3:		         0   0   0   |         46   1   3
4:		         0   0   0   |         46   1   4
5:		         0   0   0   |         47   1   6
6:		         0   0   0   |         48   1   7
7:		         0   0   0   |         48   1   8
8:		         0   0   0   |         53   1   9
9:		         0   0   0   |       2283  60  70
10:		         0   0   0   |       1116  29  99
11:		         0   0   0   |          1   0 100

			read			write
offset                rpcs   % cum % |       rpcs   % cum %
0:		         0   0   0   |         68   1   1
1:		         0   0   0   |          0   0   1
2:		         0   0   0   |          0   0   1
4:		         0   0   0   |          0   0   1
8:		         0   0   0   |          0   0   1
16:		         0   0   0   |          0   0   1
32:		         0   0   0   |          0   0   1
64:		         0   0   0   |          0   0   1
128:		         0   0   0   |          0   0   1
256:		         0   0   0   |         68   1   3
512:		         0   0   0   |        136   3   7
1024:		         0   0   0   |        272   7  14
2048:		         0   0   0   |        544  14  28
4096:		         0   0   0   |        896  23  52
8192:		         0   0   0   |       1792  47 100
osc.hasanfs-OST0003-osc-ffff882fdc929800.rpc_stats=
snapshot_time:         1634137979.42422 (secs.usecs)
read RPCs in flight:  0
write RPCs in flight: 0
pending write pages:  0
pending read pages:   0

			read			write
pages per rpc         rpcs   % cum % |       rpcs   % cum %
1:		         0   0   0   |          0   0   0
2:		         0   0   0   |          0   0   0
4:		         0   0   0   |          0   0   0
8:		         0   0   0   |          0   0   0
16:		         0   0   0   |          0   0   0
32:		         0   0   0   |          0   0   0
64:		         0   0   0   |          0   0   0
128:		         0   0   0   |          0   0   0
256:		         0   0   0   |       4048 100 100

			read			write
rpcs in flight        rpcs   % cum % |       rpcs   % cum %
0:		         0   0   0   |          0   0   0
1:		         0   0   0   |         44   1   1
2:		         0   0   0   |         44   1   2
3:		         0   0   0   |         44   1   3
4:		         0   0   0   |         44   1   4
5:		         0   0   0   |         46   1   5
6:		         0   0   0   |         46   1   6
7:		         0   0   0   |         48   1   7
8:		         0   0   0   |         52   1   9
9:		         0   0   0   |       2487  61  70
10:		         0   0   0   |       1193  29 100

			read			write
offset                rpcs   % cum % |       rpcs   % cum %
0:		         0   0   0   |         73   1   1
1:		         0   0   0   |          0   0   1
2:		         0   0   0   |          0   0   1
4:		         0   0   0   |          0   0   1
8:		         0   0   0   |          0   0   1
16:		         0   0   0   |          0   0   1
32:		         0   0   0   |          0   0   1
64:		         0   0   0   |          0   0   1
128:		         0   0   0   |          0   0   1
256:		         0   0   0   |         73   1   3
512:		         0   0   0   |        146   3   7
1024:		         0   0   0   |        292   7  14
2048:		         0   0   0   |        584  14  28
4096:		         0   0   0   |        960  23  52
8192:		         0   0   0   |       1920  47 100
osc.hasanfs-OST0004-osc-ffff882fdc929800.rpc_stats=
snapshot_time:         1634137979.43647 (secs.usecs)
read RPCs in flight:  0
write RPCs in flight: 0
pending write pages:  0
pending read pages:   0

			read			write
pages per rpc         rpcs   % cum % |       rpcs   % cum %
1:		         0   0   0   |          0   0   0
2:		         0   0   0   |          0   0   0
4:		         0   0   0   |          0   0   0
8:		         0   0   0   |          0   0   0
16:		         0   0   0   |          0   0   0
32:		         0   0   0   |          0   0   0
64:		         0   0   0   |          0   0   0
128:		         0   0   0   |          0   0   0
256:		         0   0   0   |       4048 100 100

			read			write
rpcs in flight        rpcs   % cum % |       rpcs   % cum %
0:		         0   0   0   |          0   0   0
1:		         0   0   0   |         58   1   1
2:		         0   0   0   |         60   1   2
3:		         0   0   0   |         60   1   4
4:		         0   0   0   |         60   1   5
5:		         0   0   0   |         60   1   7
6:		         0   0   0   |         61   1   8
7:		         0   0   0   |         62   1  10
8:		         0   0   0   |         69   1  12
9:		         0   0   0   |       2553  63  75
10:		         0   0   0   |       1005  24 100

			read			write
offset                rpcs   % cum % |       rpcs   % cum %
0:		         0   0   0   |         73   1   1
1:		         0   0   0   |          0   0   1
2:		         0   0   0   |          0   0   1
4:		         0   0   0   |          0   0   1
8:		         0   0   0   |          0   0   1
16:		         0   0   0   |          0   0   1
32:		         0   0   0   |          0   0   1
64:		         0   0   0   |          0   0   1
128:		         0   0   0   |          0   0   1
256:		         0   0   0   |         73   1   3
512:		         0   0   0   |        146   3   7
1024:		         0   0   0   |        292   7  14
2048:		         0   0   0   |        584  14  28
4096:		         0   0   0   |        960  23  52
8192:		         0   0   0   |       1920  47 100
osc.hasanfs-OST0005-osc-ffff882fdc929800.rpc_stats=
snapshot_time:         1634137979.44994 (secs.usecs)
read RPCs in flight:  0
write RPCs in flight: 0
pending write pages:  0
pending read pages:   0

			read			write
pages per rpc         rpcs   % cum % |       rpcs   % cum %
1:		         0   0   0   |          0   0   0
2:		         0   0   0   |          0   0   0
4:		         0   0   0   |          0   0   0
8:		         0   0   0   |          0   0   0
16:		         0   0   0   |          0   0   0
32:		         0   0   0   |          0   0   0
64:		         0   0   0   |          0   0   0
128:		         0   0   0   |          0   0   0
256:		         0   0   0   |       3840 100 100

			read			write
rpcs in flight        rpcs   % cum % |       rpcs   % cum %
0:		         0   0   0   |          0   0   0
1:		         0   0   0   |         38   0   0
2:		         0   0   0   |         38   0   1
3:		         0   0   0   |         38   0   2
4:		         0   0   0   |         38   0   3
5:		         0   0   0   |         38   0   4
6:		         0   0   0   |         39   1   5
7:		         0   0   0   |         39   1   6
8:		         0   0   0   |         47   1   8
9:		         0   0   0   |       2271  59  67
10:		         0   0   0   |       1253  32  99
11:		         0   0   0   |          1   0 100

			read			write
offset                rpcs   % cum % |       rpcs   % cum %
0:		         0   0   0   |         69   1   1
1:		         0   0   0   |          0   0   1
2:		         0   0   0   |          0   0   1
4:		         0   0   0   |          0   0   1
8:		         0   0   0   |          0   0   1
16:		         0   0   0   |          0   0   1
32:		         0   0   0   |          0   0   1
64:		         0   0   0   |          0   0   1
128:		         0   0   0   |          0   0   1
256:		         0   0   0   |         69   1   3
512:		         0   0   0   |        138   3   7
1024:		         0   0   0   |        276   7  14
2048:		         0   0   0   |        552  14  28
4096:		         0   0   0   |        912  23  52
8192:		         0   0   0   |       1824  47 100
osc.hasanfs-OST0006-osc-ffff882fdc929800.rpc_stats=
snapshot_time:         1634137979.46277 (secs.usecs)
read RPCs in flight:  0
write RPCs in flight: 0
pending write pages:  0
pending read pages:   0

			read			write
pages per rpc         rpcs   % cum % |       rpcs   % cum %
1:		         0   0   0   |          0   0   0
2:		         0   0   0   |          0   0   0
4:		         0   0   0   |          0   0   0
8:		         0   0   0   |          0   0   0
16:		         0   0   0   |          0   0   0
32:		         0   0   0   |          0   0   0
64:		         0   0   0   |          1   0   0
128:		         0   0   0   |          0   0   0
256:		         0   0   0   |       4016  99 100

			read			write
rpcs in flight        rpcs   % cum % |       rpcs   % cum %
0:		         0   0   0   |          0   0   0
1:		         0   0   0   |          2   0   0
2:		         0   0   0   |          3   0   0
3:		         0   0   0   |          4   0   0
4:		         0   0   0   |          3   0   0
5:		         0   0   0   |          4   0   0
6:		         0   0   0   |          6   0   0
7:		         0   0   0   |          9   0   0
8:		         0   0   0   |         72   1   2
9:		         0   0   0   |       2083  51  54
10:		         0   0   0   |       1768  44  98
11:		         0   0   0   |         56   1  99
12:		         0   0   0   |          5   0  99
13:		         0   0   0   |          1   0  99
14:		         0   0   0   |          1   0 100

			read			write
offset                rpcs   % cum % |       rpcs   % cum %
0:		         0   0   0   |         74   1   1
1:		         0   0   0   |          0   0   1
2:		         0   0   0   |          0   0   1
4:		         0   0   0   |          0   0   1
8:		         0   0   0   |          0   0   1
16:		         0   0   0   |          0   0   1
32:		         0   0   0   |          0   0   1
64:		         0   0   0   |          0   0   1
128:		         0   0   0   |          0   0   1
256:		         0   0   0   |         74   1   3
512:		         0   0   0   |        148   3   7
1024:		         0   0   0   |        296   7  14
2048:		         0   0   0   |        592  14  29
4096:		         0   0   0   |        977  24  53
8192:		         0   0   0   |       1856  46 100
osc.hasanfs-OST0007-osc-ffff882fdc929800.rpc_stats=
snapshot_time:         1634137979.47655 (secs.usecs)
read RPCs in flight:  0
write RPCs in flight: 0
pending write pages:  0
pending read pages:   0

			read			write
pages per rpc         rpcs   % cum % |       rpcs   % cum %
1:		         0   0   0   |          0   0   0
2:		         0   0   0   |          0   0   0
4:		         0   0   0   |          0   0   0
8:		         0   0   0   |          0   0   0
16:		         0   0   0   |          0   0   0
32:		         0   0   0   |          0   0   0
64:		         0   0   0   |          0   0   0
128:		         0   0   0   |          0   0   0
256:		         0   0   0   |       3648 100 100

			read			write
rpcs in flight        rpcs   % cum % |       rpcs   % cum %
0:		         0   0   0   |          0   0   0
1:		         0   0   0   |          7   0   0
2:		         0   0   0   |          8   0   0
3:		         0   0   0   |          8   0   0
4:		         0   0   0   |          9   0   0
5:		         0   0   0   |         10   0   1
6:		         0   0   0   |         13   0   1
7:		         0   0   0   |         34   0   2
8:		         0   0   0   |        134   3   6
9:		         0   0   0   |       1929  52  58
10:		         0   0   0   |       1434  39  98
11:		         0   0   0   |         61   1  99
12:		         0   0   0   |          1   0 100

			read			write
offset                rpcs   % cum % |       rpcs   % cum %
0:		         0   0   0   |         66   1   1
1:		         0   0   0   |          0   0   1
2:		         0   0   0   |          0   0   1
4:		         0   0   0   |          0   0   1
8:		         0   0   0   |          0   0   1
16:		         0   0   0   |          0   0   1
32:		         0   0   0   |          0   0   1
64:		         0   0   0   |          0   0   1
128:		         0   0   0   |          0   0   1
256:		         0   0   0   |         66   1   3
512:		         0   0   0   |        132   3   7
1024:		         0   0   0   |        264   7  14
2048:		         0   0   0   |        528  14  28
4096:		         0   0   0   |        864  23  52
8192:		         0   0   0   |       1728  47 100

- Md. Hasanur Rashid


On Wed, Oct 13, 2021 at 10:40 AM Patrick Farrell <pfarrell at ddn.com> wrote:

> [*Caution*: Email from External Sender. Do not click or open links or
> attachments unless you know this sender.]
>
> Interesting!  Usually that would flush the cache, but sometimes drop
> caches doesn't seem to cause recently written data to be flushed, even
> after sync.  (There is probably a minor bug here.)  But try this:
>
> After your sync and drop caches commands, clear all the LDLM locks on the
> client:
>
> lctl set_param ldlm.namespaces.*.lru_size=clear
>
> That removes the LDLM locks protecting the data, which should force it out
> of cache.  Note that locks aren't cleared if there's dirty data, so sync
> first is essential.
>
> -Patrick
> ------------------------------
> *From:* lustre-discuss <lustre-discuss-bounces at lists.lustre.org> on
> behalf of Md Hasanur Rashid via lustre-discuss <
> lustre-discuss at lists.lustre.org>
> *Sent:* Wednesday, October 13, 2021 7:36 AM
> *To:* lustre-discuss at lists.lustre.org <lustre-discuss at lists.lustre.org>
> *Subject:* [lustre-discuss] No read throughput shown for the sequential
> read write Filebench workload
>
> Hello Everyone,
>
> I am running a Filebench workload which is provided below:
>
> define fileset name="testF",entries=100,filesize=16m,prealloc,path="/mnt/hasanfs/tmp1"
>
> define process name="readerP",instances=2 {
>   thread name="readerT",instances=4 {
>   flowop openfile name="openOP",filesetname="testF"
>   flowop writewholefile name="writeOP",iters=4,filesetname="testF"
>   flowop readwholefile name="readOP",iters=1,filesetname="testF"
>   flowop closefile name="closeOP"
>   }
> }
>
> create files
> system "sync"
> system "echo 3 > /proc/sys/vm/drop_caches"
>
> run 60
>
> I am running the workload in a Lustre cluster. When I check the log from
> the server-side, it shows the following (I have provided stats of one OSS):
>
> obdfilter.hasanfs-OST0000.stats=
> snapshot_time             1633361244.519122 secs.usecs
> read_bytes                1 samples [bytes] 4096 4096 4096
> write_bytes               8479 samples [bytes] 1048576 1048576 8890875904
> destroy                   13 samples [reqs]
> statfs                    76 samples [reqs]
> preprw                    8480 samples [reqs]
> commitrw                  8480 samples [reqs]
> ping                      57 samples [reqs]
>
> obdfilter.hasanfs-OST0000.brw_stats=
> snapshot_time:         1633361244.519588 (secs.usecs)
>
>                            read      |     write
> pages per bulk r/w     rpcs  % cum % |  rpcs        % cum %
> 256:		         0   0   0   | 8479 100 100
>
>                            read      |     write
> discontiguous pages    rpcs  % cum % |  rpcs        % cum %
> 0:		         0   0   0   | 8479 100 100
>
>                            read      |     write
> discontiguous blocks   rpcs  % cum % |  rpcs        % cum %
> 0:		         0   0   0   | 8479 100 100
>
>                            read      |     write
> disk fragmented I/Os   ios   % cum % |  ios         % cum %
> 1:		         0   0   0   | 7499  88  88
> 2:		         0   0   0   |  980  11 100
>
>                            read      |     write
> disk I/Os in flight    ios   % cum % |  ios         % cum %
> 1:		         0   0   0   | 7921  83  83
> 2:		         0   0   0   | 1407  14  98
> 3:		         0   0   0   |  116   1  99
> 4:		         0   0   0   |   15   0 100
>
>                            read      |     write
> I/O time (1/1000s)     ios   % cum % |  ios         % cum %
> 2:		         0   0   0   | 1963  23  23
> 4:		         0   0   0   | 5627  66  89
> 8:		         0   0   0   |  837   9  99
> 16:		         0   0   0   |   25   0  99
> 32:		         0   0   0   |   27   0 100
>
>                            read      |     write
> disk I/O size          ios   % cum % |  ios         % cum %
> 4K:		         0   0   0   |   62   0   0
> 8K:		         0   0   0   |  127   1   1
> 16K:		         0   0   0   |  113   1   3
> 32K:		         0   0   0   |    0   0   3
> 64K:		         0   0   0   |    0   0   3
> 128K:		         0   0   0   |   65   0   3
> 256K:		         0   0   0   |    0   0   3
> 512K:		         0   0   0   | 1127  11  15
> 1M:		         0   0   0   | 7965  84 100
>
> *Can anyone please explain to me why I am not seeing any read operations
> in the stats?*
>
> Thanks,
> Md. Hasanur Rashid
>
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