Opened 6 years ago

Closed 6 years ago

#9953 closed bug (fixed)

ping gives crazy std deviation values

Reported by: Pete Owned by: phoudoin
Priority: normal Milestone: R1
Component: Network & Internet Version: R1/alpha4.1
Keywords: Cc:
Blocked By: Blocking:
Has a Patch: yes Platform: All

Description

I'm a bit surprised no one has called this out before, but when checking out my network performance with ping, I noticed that the std-deviation values it was printing were way out of whack -- larger than the actual round-trip times!

Took me a while to blame the Newton's square root calculation, but one of the comparisons there had the wrong sense!

A fix is attached.

Attachments (1)

0001-Fix-to-std-dev-calculation-in-ping.patch (675 bytes) - added by Pete 6 years ago.
patch to ping.c to fix qsqrt

Download all attachments as: .zip

Change History (6)

Changed 6 years ago by Pete

patch to ping.c to fix qsqrt

comment:1 Changed 6 years ago by Pete

Has a Patch: set

comment:2 Changed 6 years ago by korli

Dunno where our ping.c comes from but the comparison was already corrected in 1999. I guess this validates your patch, which can thus be applied.

comment:3 in reply to:  2 Changed 6 years ago by Pete

Replying to korli:

Dunno where our ping.c comes from but the comparison was already corrected in 1999.

Ahh -- I guess that's the derivation route anyway. I did various web searches, but couldn't find a ping that came close to matching. Many (earlier ones?) don't even calculate std deviation, and others used doubles and the library sqrt.

I guess this validates your patch, which can thus be applied.

Thanks.

comment:4 Changed 6 years ago by phoudoin

Owner: changed from nobody to phoudoin
Status: newassigned

comment:5 Changed 6 years ago by phoudoin

Resolution: fixed
Status: assignedclosed

Patch applied in hrev46042. Thanks.

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