Change in osmo-msc[master]: large refactoring: support inter-BSC and inter-MSC Handover

Neels Hofmeyr gerrit-no-reply at lists.osmocom.org
Wed May 8 14:43:25 UTC 2019


Neels Hofmeyr has posted comments on this change. ( https://gerrit.osmocom.org/13137 )

Change subject: large refactoring: support inter-BSC and inter-MSC Handover
......................................................................


Patch Set 9:

(2 comments)

https://gerrit.osmocom.org/#/c/13137/9/src/libmsc/call_leg.c
File src/libmsc/call_leg.c:

https://gerrit.osmocom.org/#/c/13137/9/src/libmsc/call_leg.c@78
PS9, Line 78: talloc_zero
> > The talloc API does not provide a macro similar to talloc_zero() that names the struct [...] […]
hmm, I didn't see that! even the first on top. All I saw was talloc_size(). I apologize for being blind.


https://gerrit.osmocom.org/#/c/13137/9/src/libmsc/e_link.c
File src/libmsc/e_link.c:

https://gerrit.osmocom.org/#/c/13137/9/src/libmsc/e_link.c@77
PS9, Line 77: *e = (struct e_link) {
> the point is that the compiler is unable to optimize away initializing the same bit of memory *twice […]
Every time micro optimisation comes up I think we should actually start some profiling effort that tells us how much time is spent where. Then we could sensibly argue about performance changes with hard data to support it. I think there are quite a few things we do far more often that are a lot worse than this, O(N) things instead of O(1). Comes to mind: iterating entire linked-lists over all items to find the conn for a received message / the vsub for a subscriber / ...; iterating value_string[] instead of using array index; copying msgb around to get enough headroom.

Compared to those, I suspect that this is really not worth even commenting about. Writing about this double-zero-init likely took more time than osmo-msc would spend doing this in ten years of operation.



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Gerrit-Project: osmo-msc
Gerrit-Branch: master
Gerrit-MessageType: comment
Gerrit-Change-Id: I27e4988e0371808b512c757d2b52ada1615067bd
Gerrit-Change-Number: 13137
Gerrit-PatchSet: 9
Gerrit-Owner: Neels Hofmeyr <nhofmeyr at sysmocom.de>
Gerrit-Reviewer: Harald Welte <laforge at gnumonks.org>
Gerrit-Reviewer: Jenkins Builder (1000002)
Gerrit-Reviewer: Neels Hofmeyr <nhofmeyr at sysmocom.de>
Gerrit-Reviewer: Vadim Yanitskiy <axilirator at gmail.com>
Gerrit-CC: Pau Espin Pedrol <pespin at sysmocom.de>
Gerrit-Comment-Date: Wed, 08 May 2019 14:43:25 +0000
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