Re: Meanning of ceph perf dump

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Hi Somnath,

Do you have a link with the definitions of all the perf counters?

Thanks,
Steve

On Sun, Jul 5, 2015 at 11:23 AM, Somnath Roy <Somnath.Roy@xxxxxxxxxxx> wrote:
> Hi Ray,
>
> Here is the description of the different latencies under filestore perf
> counters.
>
>
>
> Journal_latency :
>
> ----------------------
>
>
>
> This is the latency of putting the ops in journal. Write is acknowledged
> after that (well a bit after that, there is one context switch after this).
>
>
>
> commitcycle_latency:
>
> --------------------------
>
>
>
> Filestore backend while carrying out transaction, do a buffered write. In a
> separate thread it does call syncfs() to persist the data to the disk and
> update the persistent commit number in a separate file. This thread runs by
> default 5 sec interval.
>
> This latency measures the time taken to carry out this job after the timer
> expires i.e the actual persisting cycle.
>
>
>
> apply_latency:
>
> ----------------
>
>
>
> This is the entire latency till the transaction finishes i.e journal write +
> transaction time. It will do a buffer write here.
>
>
>
> queue_transaction_latency_avg:
>
> ----------------------------------------
>
> This is the latency of putting the op in the journal queue. This will give
> you an idea how much throttling is going on at the first place. This depends
> on the following two parameters if you are using XFS.
>
>
>
> filestore_queue_max_ops
>
> filestore_queue_max_bytes
>
>
>
>
>
> All the latency numbers are represented by avgcount(number of ops within
> this range) and the sum (which is total latency in second). Sum/avgcount
> will give you an idea the latency per op.
>
>
>
> Hope this is helpful,
>
>
>
> Thanks & Regards
>
> Somnath
>
>
>
>
>
> From: ceph-users [mailto:ceph-users-bounces@xxxxxxxxxxxxxx] On Behalf Of Ray
> Sun
> Sent: Sunday, July 05, 2015 7:28 AM
> To: ceph-users@xxxxxxxxxxxxxx
> Subject:  Meanning of ceph perf dump
>
>
>
> Cephers,
>
> Is there any documents or code definition to explain ceph perf dump? I am a
> little confusing about the output, for example, under filestore, there's
> journal_latency and apply_latency and each of them has avgcount and sum. I
> am not quite sure what's the unit and meaning of the numbers? How can I use
> these numbers to tuning my ceph cluster. Thanks a lot.
>
>
>
> "filestore": {
>
>         "journal_queue_max_ops": 300,
>
>         "journal_queue_ops": 0,
>
>         "journal_ops": 35893,
>
>         "journal_queue_max_bytes": 33554432,
>
>         "journal_queue_bytes": 0,
>
>         "journal_bytes": 20579009432,
>
>         "journal_latency": {
>
>             "avgcount": 35893,
>
>             "sum": 1213.560761279
>
>         },
>
>         "journal_wr": 34228,
>
>         "journal_wr_bytes": {
>
>             "avgcount": 34228,
>
>             "sum": 20657713152
>
>         },
>
>         "journal_full": 0,
>
>         "committing": 0,
>
>         "commitcycle": 3207,
>
>         "commitcycle_interval": {
>
>             "avgcount": 3207,
>
>             "sum": 16157.379852152
>
>         },
>
>         "commitcycle_latency": {
>
>             "avgcount": 3207,
>
>             "sum": 121.892109010
>
>         },
>
>         "op_queue_max_ops": 50,
>
>         "op_queue_ops": 0,
>
>         "ops": 35893,
>
>         "op_queue_max_bytes": 104857600,
>
>         "op_queue_bytes": 0,
>
>         "bytes": 20578506930,
>
>         "apply_latency": {
>
>             "avgcount": 35893,
>
>             "sum": 1327.974596287
>
>         },
>
>         "queue_transaction_latency_avg": {
>
>             "avgcount": 35893,
>
>             "sum": 0.025993727
>
>         }
>
>     },
>
>
>
> Best Regards
> -- Ray
>
>
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