In This Section
Overview
An operational XVM continuously collects raw statistics during the course of its operation. The xvm can also be configured to spin up a background thread that periodically performs the following:
- Performs higher level statistical computations such as calculate message rates and average latencies.
- Emits heartbeat messages to be processed by handlers.
- Optionally outputs server statistics to named trace loggers using the platform's tracing and logging system.
- Optionally writes heartbeat messages containing useful server-wide statistics to a binary transaction log (with zero steady-state allocations).
- Detects violation/abatement of alert thresholds and dispatch appropriate alert events.
The raw metrics collected by the server are used by the background statistical thread for its computations and can also be retrieved programmatically by an application for its own use.
In this document, we describe:
- the various raw metrics captured by the server,
- how to switch on and configure the statistics thread operation,
- the higher level statistics calculations performed by the statistics thread,
- and the format of the output of the statistics thread.
Configuration Settings
| Configuration Setting | Default | Description |
|---|---|---|
| nv.server.stats.enable | false | Enable or disable server stats collection and heartbeat emission. If tracers have been configured at the debug level, server statistics will be traced on the same thread that performs stats collection and emits heartbeats. |
| nv.server.stats.interval | 1000 | The interval (in milliseconds) at which server stats will be collected and heartbeat events emitted when nv.server.stats.enable=true. |
| nv.server.stats.includeSeries | true | Indicates whether or not series stats should be included in heartbeats. |
| nv.server.stats.includeSeriesDataPoints | false | Indicates whether or not series stats should report the data points captured for a series statistic. |
| nv.server.stats.maxTrackableSeriesValue | 10 minutes | The maximum value (in microseconds) that can be tracked for reported series histogram timings. |
| nv.server.stats.pool.enable | true | Indicates whether or not pool stats are collected by the server when nv.server.stats.enable=true. |
| nv.server.stats.pool.depletionThreshold | 1.0 | Configuration property used to set the percentage decrement at which a preallocated pool must drop to be included in a server heartbeat. Setting this to a value greater than 100 or less than or equal to 0 disables depletion threshold reporting. This gives monitoring applications advanced warning if it looks like a preallocated pool may soon be exhausted. By default the depletion threshold is set to trigger inclusion in heartbeats at every 1% depletion of the preallocated count. This can be changed by specifying the configuration property nv.server.stats.pool.depletionThreshold to a float value between 0 and 100. For example: Setting this to a value greater than 100 or less than or equal to 0 disables depletion threshold reporting.
|
Handling Server Heartbeats
When heartbeats are enabled via the nv.server.stats.enable and nv.server.stats.interval properties they can be handled in several ways, discussed below.
Tracing Heartbeats
By default all server statistics tracers are disabled as trace logging is not zero garbage and introduces cpu overhead in computing statistics. While tracing heartbeats isn't recommended in production, enabling server statistics trace output can be useful for debugging and performance tuning. To enable you will need to configure the appropriate tracers at the debug level. See the Output Trace Loggers section for more detail.
Binary Heartbeat Logging
Applications that are latency sensitive might prefer to leave all tracers disabled to avoid unnecessary allocations and the associated GC activity. As an alternative, it's possible to enable logging of zero-garbage heartbeat messages to a binary transaction log:
Heartbeat logs can be queried out of process using the Stats Dump Tool.
Note that at this time binary heartbeat logs do not support rolling collection, so at this time the built-in heartbeat logging mechanism is not suitable for long running application instances.
Heartbeat Event Handlers
Your application can register an event handler for server heartbeats to handle them in process.
See the SrvMonHeartbeatMessage JavaDoc for API details.
Robin
A Robin Controller can also be used to connect to a server and listen for heartbeats emitted by a Talon Server.
The Statistics Thread
The server statistics thread performs the following operations:
- Compute higher level statistics such as metric averages.
- Output raw and computed statistics to any trace loggers configured at the debug level.
- Emit heartbeat messages consumed by handlers and the heartbeat log, if enabled.
The statistics thread can be enabled or disabled via the configuration parameters.
Administrative Control
The server statistics thread can also be started via the following environment variables or system properties:
Once started administratively, the statistics thread remains active until the server is stopped.
Note: When configuring using environment variables, in Unix based systems where the shell does not support "." in environment variables. If you would like to use environment variables to set server statistics config on Unix, replace any "." characters in the variable name with "_".
Pool Stats
By default, the server statistics thread collects object pool stats. If you would prefer pool stats not to be recorded:
Computed Statistics
The server statistics thread computes (then optionally traces and/or logs) the following at the configured frequency:
General Info
- Date and time that statistics gathering started
- Server name
- Server PID
- Number of apps running in the server
- Time spent gathering server statistics (for the current interval, excluding formatting)
System Info
- Number of available processors
- System load average
Memory Info
- Initial heap size
- Heap used
- Heap committed
- Max heap size
- Initial non-heap size
- Non-heap memory used
- Non-heap memory committed
- Non-heap memory max size
Thread Info
- Total thread count
- Daemon thread count
- Peak thread count
JIT Info
- JIT name
- Total compilation time
GC Info
- Collection count (for all GCs)
- Collection time (for all GCs)
Thread Stats
Reported for each active thread:
- Per-thread CPU time as a percentage of total CPU time
- Per-thread user CPU time as a percentage of thread CPU time
- Delta CPU time
- Delta CPU time as a percentage of total delta CPU time
- Delta user CPU time
- Delta user CPU time as a percentage of thread delta CPU time
Pool Stats
To reduce the size of heartbeats, Pool Stats for a given pool are only included when:
- A miss has been recorded for the pool in a given interval and it results in a new object being allocated.
- The number of preallocated obects taken from a pool drops below the configured value for the pool depletion threshold.
Pool stats include:
- Number of puts
- Delta number of puts
- Number of gets
- Delta number of gets
- Number of hits
- Delta number of hits
- Number of misses
- Delta number of misses
- Number of growths
- Delta number of growths
- Number of evicts
- Delta number of evicts
- Number of detached watches
- Delta number of detached watches
- Pool size
- Number of preallocated objects (????)
- Pool capacity
- Pool key
App Stats
Reported for each app:
- Engine stats
- Store stats
- Store binding persister stats
- Store binding ICR sender stats
- Bus binding stats
- User stats
See Also:
- AEP Engine Statistics for more detail about app-level stats.
- User Defined App Stats for adding stats specific to your application to heartbeats.
Trace Output Loggers
The server statistics thread uses several named trace loggers to log the raw and computed statistics output. The following is the list of the loggers used by the server stats thread.
- nv.server.stats.sys.trace – tracer for System Statistics
- nv.server.stats.thread.trace – tracer for Thread Statistics
- nv.server.stats.pool.trace – tracer for Pool Statistics
- nv.server.stats.app.trace – tracer for Application and Engine Statistics
- nv.server.stats.userstats.trace – tracer for User Defined Statistics
If you would like to see server statistics trace output, the appropriate tracers need to be configured at the debug level. For example, to enable System Stats trace output:
nv.server.stats.sys.trace=debug
See Also: X Platform Tracing and Logging for general details on configuration of trace logging.
Output Format
System Stats
Appears in trace output when nv.server.stats.enable=true and nv.server.stats.sys.trace=debug
[System Stats]
Tue Jun 28 17:26:03 PDT 2016 'ems1' server (pid=50360) 2 apps (collection time=73982839 ns)
System: 20 processors load average: 2.30
Memory: HEAP 8.0G init 6.6G used 7.8G commit 7.8G max NON-HEAP 2M init 44M used 46M commit 0K max
Threads: 26 total (23 daemon) 27 peak
JIT: HotSpot 64-Bit Tiered Compilers, time: 11997 ms
[6 6404 ms] [2 8771 ms]
Thread Stats
Appears in trace output when nv.server.stats.enable=true and nv.server.stats.thread.trace=debug
[Thread Stats]
ID CPU CPU% USER% DCPU DCPU% DUSER% STATE NAME
1 0 1 100 0 0 0 RUNNABLE X-Server-ems1-Main (aff=[])
2 0 1 100 0 0 0 WAITING Reference Handler
3 0 1 100 0 0 0 WAITING Finalizer
4 0 1 100 0 0 0 RUNNABLE Signal Dispatcher
23 0 3 100 0 0 0 RUNNABLE X-EDP-McastReceiver (aff=[1(s0c1t0)])
25 0 3 100 0 0 0 TIMED_WAITING X-EDP-Timer (aff=[1(s0c1t0)])
26 0 4 100 0 0 0 RUNNABLE X-ODS-StoreLog-ems1-heartbeats-1 (aff=[])
27 0 4 100 0 0 0 RUNNABLE X-Server-ems1-StatsRunner (aff=[1(s0c1t0)])
30 0 4 100 0 0 0 TIMED_WAITING Wrapper-Control-Event-Monitor
31 0 4 100 0 0 0 TIMED_WAITING Wrapper-Startup-Runner
33 0 4 100 0 0 0 RUNNABLE X-Server-ems1-IOThread-1 (aff=[8(s0c11t0)])
35 0 5 100 0 0 0 TIMED_WAITING X-EventMultiplexer-Wakeup (aff=[1(s0c1t0)])
36 0 5 100 0 0 0 RUNNABLE X-AEP-BusManager-BindingOpener-admin.admin (aff=[1(s0c1t0)])
37 0 5 100 0 0 0 RUNNABLE X-AEP-BusManager-BindingOpener-admin.client-fb0ab760-3d8f-11e6-abfe-0002c9faaac2 (aff=[1(s0c1t0)])
38 0 5 100 0 0 0 RUNNABLE X-AEP-BusManager-BindingOpener-admin.control-fb0a1b20-3d8f-11e6-abfe-0002c9faaac2 (aff=[1(s0c1t0)])
40 0 5 100 0 0 0 TIMED_WAITING X-EventMultiplexer-Wakeup (aff=[1(s0c1t0)])
41 0 5 100 0 0 0 RUNNABLE X-AEP-BusManager-BindingOpener-ems.market (aff=[1(s0c1t0)])
42 0 5 100 0 0 0 RUNNABLE X-AEP-BusManager-BindingOpener-ems.ems (aff=[1(s0c1t0)])
43 0 6 100 0 0 0 RUNNABLE X-AEP-BusManager-BindingOpener-ems.client-fb48aac0-3d8f-11e6-abfe-0002c9faaac2 (aff=[1(s0c1t0)])
44 0 6 100 0 0 0 RUNNABLE X-AEP-BusManager-BindingOpener-ems.control-fb0a1b20-3d8f-11e6-abfe-0002c9faaac2 (aff=[1(s0c1t0)])
45 0 6 100 0 0 0 WAITING X-STEMux-admin-1 (aff=[])
46 0 6 100 0 0 0 RUNNABLE X-STEMux-ems-2 (aff=[2(s0c2t0)])
47 0 6 100 0 0 0 RUNNABLE X-ODS-StoreLinkAcceptor-1 (aff=[1(s0c1t0)])
48 0 6 100 0 0 0 RUNNABLE X-ODS-StoreEventMultiplexer-1 (aff=[3(s0c3t0)])
49 0 6 100 0 0 0 RUNNABLE X-AEP-BusManager-IO-ems.market (aff=[6(s0c9t0)])
50 0 6 100 0 0 0 RUNNABLE X-Client-LinkManagerReader[298b29db-82ae-4cc7-97b7-1143a417e86c] (aff=[7(s0c10t0)])
Pool Stats
Appears in trace output when nv.server.stats.enable=true and nv.server.stats.pool.trace=debug
<27,50360,perf5.neeveresearch.com> 20160628-17:26:03:609 (dbg)...
[Pool Stats]
PUT DPUT GET DGET HIT DHIT MISS DMISS GROW DGROW EVIC DEVIC DWSH DDWSH SIZE PRE CAP NAME
0 0 1 0 0 0 1 0 0 0 0 0 0 0 0 0 1024 packet.server_client_connect_request.71
0 0 1 0 0 0 1 0 0 0 0 0 0 0 0 0 1024 packet.server_client_connect_reply.50
46 0 46 0 44 0 2 0 0 0 0 0 0 0 2 0 1024 iobuf.heap-256.4
4 0 145 0 4 0 141 0 0 0 0 0 0 0 0 0 1024 iobuf.native-256.23
49 0 64 0 48 0 16 0 0 0 0 0 0 0 1 0 1024 iobuf.heap-64.2
18 0 27.3M 0 18 0 27.3M 0 0 0 0 0 0 0 0 0 1024 iobuf.native-32.20
6 0 29 0 6 0 23 0 0 0 0 0 0 0 0 0 1024 iobuf.native-64.21
0 0 5 0 0 0 5 0 0 0 0 0 0 0 0 0 1024 packet.recovery_log_eof_marker.87
0 0 2 0 0 0 2 0 0 0 0 0 0 0 0 0 1024 packet.recovery_log_checkpoint_state.39
48 0 48 0 46 0 2 0 0 0 0 0 0 0 2 0 1024 packet.discovery_esa.65
2 0 33 0 2 0 31 0 0 0 0 0 0 0 0 0 1024 iobuf.heap-32.1
0 0 2 0 0 0 2 0 0 0 0 0 0 0 0 0 1024 iobuf.native-8K.28
0 0 2 0 0 0 2 0 0 0 0 0 0 0 0 0 1024 xbuf.entity.SrvMonAppInfoXbufEntity.0.100.106
App Stats and User Stats
Appears in trace output when nv.server.stats.enable=true and nv.server.stats.app.trace=debug.
The below example is output from the Tick To Trade sample application available in GitHub.
[App (ems) Engine Stats]
MRCV RATE DRATE MRCVB RATE DRATE MRCVG RATE DRATE MSND RATE DRATE MSNDB RATE DRATE MSNDG RATE DRATE EVNT RATE DRATE FEVNT RATE DRATE TXN RATE DRATE TXNSZ RLBK
106K 613 92 106K 613 92 0 0 0 106K 613 92 106K 613 92 0 0 0 320K 1.8K 278 106K 613 92 106K 613 92 0 0
...Disruptor {[0of1,024] 0% (MultiThreadedSufficientCores, BusySpin)}
...Feeder Queues{
......X-Server-ems1-Main (aff=[]): size=0, decongestCount=284178
......X-ODS-StoreEventMultiplexer-1 (aff=[3(s0c3t0)]): size=0, decongestCount=284164
......X-Server-ems1-IOThread-1 (aff=[8(s0c11t0)]): size=0, decongestCount=284162
......X-AEP-BusManager-IO-ems.market (aff=[6(s0c9t0)]): size=0, decongestCount=284160
......X-STEMux-ems-2 (aff=[2(s0c2t0)]): size=0, decongestCount=284160
......X-Client-LinkManagerReader[298b29db-82ae-4cc7-97b7-1143a417e86c] (aff=[7(s0c10t0)]): size=0, decongestCount=284159
...}
[App (ems) User Stats]
...Gauges{
......EMS Messages Received: 142604
......EMS Orders Received: 35651
...}
...Series{
......[In Proc Tick To Trade(sno=35651, #points=150, #skipped=0)
.........In Proc Tick To Trade(interval): [sample=150, min=72 max=84 mean=75 median=75 75%ile=77 90%ile=79 99%ile=83 99.9%ile=84 99.99%ile=84]
.........In Proc Tick To Trade (running): [sample=35651, min=72 max=20008 mean=93 median=76 75%ile=82 90%ile=111 99%ile=227 99.9%ile=805 99.99%ile=11975]
......[In Proc Time To First Slice(sno=35651, #points=150, #skipped=0)
.........In Proc Time To First Slice(interval): [sample=150, min=85 max=98 mean=88 median=88 75%ile=90 90%ile=92 99%ile=95 99.9%ile=98 99.99%ile=98]
.........In Proc Time To First Slice (running): [sample=35651, min=84 max=44695 mean=249 median=88 75%ile=95 90%ile=133 99%ile=283 99.9%ile=36287 99.99%ile=41439]
...}
[App (ems) Store Binding Stats]
CSND RATE DRATE CESND RATE DRATE CRCV RATE DRATE CERCV RATE DRATE CCSND RATE DRATE CCRCV RATE DRATE SIZE
106K 613 88 106K 613 88 0 0 0 0 0 0 0 0 0 106K 613 88 0
[App (ems) Store Binding Persister Stats]
<?>
...no persister
[App (ems) Store Binding ICR Sender Stats]
<?>
...no ICR sender
[App (ems) Bus Binding (market)]
<Detached ,Disruptor {[0of1,024] 0% (SingleThreaded, BusySpin)}>
MRCV RATE DRATE MRCVI RATE DRATE MRCVB RATE DRATE MENQ RATE DRATE MSND RATE DRATE FLS RATE DRATE MFLS RATE DRATE FLA RATE DRATE MFLA RATE DRATE
71302 408 57 0 0 0 0 0 0 35651 204 28 35651 204 28 71302 408 57 35651 204 28 0 0 0 0 0 0
STB RATE DRATE STBIB RATE DRATE STBB RATE DRATE PRCV RATE DRATE COM RATE DRATE RLBK CLNTS CHNLS FAILS
0 0 0 0 0 0 0 0 0 0 0 0 35651 204 28 0 0 2 0
[App (ems) Bus Binding (control-fb0a1b20-3d8f-11e6-abfe-0002c9faaac2)]
<Attached>
MRCV RATE DRATE MRCVI RATE DRATE MRCVB RATE DRATE MENQ RATE DRATE MSND RATE DRATE FLS RATE DRATE MFLS RATE DRATE FLA RATE DRATE MFLA RATE DRATE
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
STB RATE DRATE STBIB RATE DRATE STBB RATE DRATE PRCV RATE DRATE COM RATE DRATE RLBK CLNTS CHNLS FAILS
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0
[App (ems) Bus Binding (ems)]
<Attached>
MRCV RATE DRATE MRCVI RATE DRATE MRCVB RATE DRATE MENQ RATE DRATE MSND RATE DRATE FLS RATE DRATE MFLS RATE DRATE FLA RATE DRATE MFLA RATE DRATE
35651 204 28 0 0 0 0 0 0 71302 408 56 71302 408 56 71302 408 56 71302 408 56 0 0 0 0 0 0
STB RATE DRATE STBIB RATE DRATE STBB RATE DRATE PRCV RATE DRATE COM RATE DRATE RLBK CLNTS CHNLS FAILS
0 0 0 0 0 0 0 0 0 0 0 0 71302 408 56 0 0 2 0
The server stats rendering of application stats is more compact, but because stats trace is most often enabled for testing and performance tuning, it is more common to enable engine stats trace rather than server stats trace for application stats.