Opened 5 years ago

Closed 6 weeks ago

#820 closed Bug / Defect (fixed)

Compress manual doesn't list lz4-v2

Reported by: jiquera Owned by: David Sommerseth
Priority: minor Milestone: release 2.5.4
Component: Documentation Version: OpenVPN 2.4.0 (Community Ed)
Severity: Not set (select this one, unless your'e a OpenVPN developer) Keywords:
Cc: plaisthos

Description

Please fix the entry in the manual and explain the difference and the preferred setting. Right know the sample scrips are using lz4-v2 and the manual only mentions lz4.

Related to that... why do you support both? the difference is pretty much negligible. (one byte at most per packet)

Change History (13)

comment:1 Changed 5 years ago by Gert Döring

Cc: plaisthos added

the difference is packet data alignment, which is better with the -v2 compression algorithms - which reflects into "less CPU usage, less power drain on mobile devices, possibly higher throughput".

And you're right, we need to document this.

comment:2 Changed 5 years ago by Gert Döring

Milestone: release 2.4.1

comment:3 Changed 5 years ago by jiquera

yeah you explained it the other day over IRC ;) which finally made me understand the code. This is basically the follow up: document it :)

comment:4 Changed 4 years ago by mmokrejs

Why is this trivial change not yet present in 2.4.3 manpage?

comment:5 Changed 21 months ago by Gert Döring

Milestone: release 2.4.1release 2.4.9
Owner: set to David Sommerseth
Status: newassigned

@dazo: while you're at moving the manpage over to rst, can you include lz4-v2?

comment:6 Changed 20 months ago by tct

This is a low hanging fruit, I will submit a patch.

comment:7 Changed 4 months ago by Gert Döring

bump?

comment:8 Changed 4 months ago by Gert Döring

Milestone: release 2.4.9release 2.5.2

comment:9 Changed 4 months ago by plaisthos

It is already in the manpage:

The algorithm parameter may be :code:lzo, :code:lz4,

:code:lz4-v2, :code:stub, :code:stub-v2 or empty.
LZO and LZ4 are different compression algorithms, with LZ4 generally
offering the best performance with least CPU usage.

comment:10 Changed 4 months ago by Gert Döring

But that is missing why there are "lz4" and "lz4-v2"...

comment:11 Changed 6 weeks ago by Gert Döring

Milestone: release 2.5.2release 2.5.4

bumping to 2.5.4, waiting for the patch promised 19 months ago

comment:12 Changed 6 weeks ago by tct

The man page now has a good description of compression, including:

The lz4-v2 and stub-v2 variants implement a better framing 
that does not add overhead when packets cannot be compressed. 
All other variants always add one extra framing byte compared 
to no compression framing.

Details: https://github.com/OpenVPN/openvpn/blob/master/doc/man-sections/protocol-options.rst
Scroll down to --compress algorithm

comment:13 Changed 6 weeks ago by tct

Resolution: fixed
Status: assignedclosed
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