iovisor/bcc

print_log2_hist to strip leading zeros

Open

#1,109 opened on Apr 12, 2017

View on GitHub
 (3 comments) (0 reactions) (0 assignees)C (4,073 forks)batch import
enhancementhelp wanted

Repository metrics

Stars
 (22,632 stars)
PR merge metrics
 (PR metrics pending)

Description

Instead of this:

# ./funclatency vfs_write
Tracing 1 functions for "vfs_write"... Hit Ctrl-C to end.
^C
     nsecs               : count     distribution
         0 -> 1          : 0        |                                        |
         2 -> 3          : 0        |                                        |
         4 -> 7          : 0        |                                        |
         8 -> 15         : 0        |                                        |
        16 -> 31         : 0        |                                        |
        32 -> 63         : 0        |                                        |
        64 -> 127        : 0        |                                        |
       128 -> 255        : 0        |                                        |
       256 -> 511        : 0        |                                        |
       512 -> 1023       : 0        |                                        |
      1024 -> 2047       : 1        |                                        |
      2048 -> 4095       : 400      |*                                       |
      4096 -> 8191       : 4250     |*******************                     |
      8192 -> 16383      : 8652     |****************************************|
     16384 -> 32767      : 4663     |*********************                   |
     32768 -> 65535      : 453      |**                                      |
     65536 -> 131071     : 17       |                                        |
    131072 -> 262143     : 0        |                                        |
    262144 -> 524287     : 0        |                                        |
    524288 -> 1048575    : 0        |                                        |
   1048576 -> 2097151    : 0        |                                        |
   2097152 -> 4194303    : 1        |                                        |
Detaching...

Print this:

# ./funclatency vfs_write
Tracing 1 functions for "vfs_write"... Hit Ctrl-C to end.
^C
     nsecs               : count     distribution
      1024 -> 2047       : 1        |                                        |
      2048 -> 4095       : 400      |*                                       |
      4096 -> 8191       : 4250     |*******************                     |
      8192 -> 16383      : 8652     |****************************************|
     16384 -> 32767      : 4663     |*********************                   |
     32768 -> 65535      : 453      |**                                      |
     65536 -> 131071     : 17       |                                        |
    131072 -> 262143     : 0        |                                        |
    262144 -> 524287     : 0        |                                        |
    524288 -> 1048575    : 0        |                                        |
   1048576 -> 2097151    : 0        |                                        |
   2097152 -> 4194303    : 1        |                                        |
Detaching...

To keep the output more concise. This is especially noticeable by tools that print multiple histograms.

Contributor guide

Research direction
Identify the print log2 hist function implementation (likely in C or Python helper) and modify the output loop to skip rows where count is zero.
Tech stack
cpython
Domain
clibackend
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
GitC or Python programming
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
70