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Feature #4473

DTrace frequency trails

Added by Rich Lowe about 6 years ago. Updated about 6 years ago.

Status:
Resolved
Priority:
Normal
Assignee:
-
Category:
DTrace
Start date:
2014-01-14
Due date:
% Done:

90%

Estimated time:
Difficulty:
Medium
Tags:

Description

From the report at Joyent:

    syscall::read:return /self->ts/ { @["ns"] = quantize(timestamp - self->ts); self->ts = 0; }'
dtrace: description 'syscall::read:entry ' matched 2 probes
^C

  ns                                                
           value  ------------- Distribution ------------- count    
             256 |                                         0        
             512 |                                         2        
            1024 |@                                       76       
            2048 |@@@@@@                                 276      
            4096 |@@@@@@@@@                              424      
            8192 |@@@@@@                                 281      
           16384 |@@                                      95       
           32768 |                                         6        
           65536 |                                         2       
          131072 |@                                       22       
          262144 |@@@@@                                  260       
          524288 |@@                                      83        
         1048576 |                                         0        
         2097152 |                                         4        
         4194304 |                                         0        
         8388608 |                                         0        
        16777216 |                                         1        
        33554432 |                                         0

Could become:

# dtrace -n 'syscall::read:entry { self->ts = timestamp; }
    syscall::read:return /self->ts/ { @["ns"] = quantize(timestamp - self->ts); self->ts = 0; }
    END { printft("latency, ns: %@d", @); }'
dtrace: description 'syscall::read:entry ' matched 2 probes
^C

   latency, ns: 512|_-^-____-_ .  .|16777216

--

this is being added as the "aggpack" option.

History

#1

Updated by Electric Monk about 6 years ago

git commit 33093f5bcdc51014933497dd39374080c1ac5705

Author: Bryan Cantrill <bryan@joyent.com>

4471 DTrace count() with histogram
4472 DTrace full width distribution histograms
4473 DTrace frequency trails
Reviewed by: Dan McDonald <danmcd@omniti.com>
Approved by: Gordon Ross <gwr@nexenta.com>

#2

Updated by Rich Lowe about 6 years ago

  • Status changed from In Progress to Resolved

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