Opened 16 years ago
Closed 15 years ago
#5175 closed defect (fixed)
Fast CMOV test in configure is broken
| Reported by: | Dagmar d'Surreal | Owned by: | Janne Grunau |
|---|---|---|---|
| Priority: | trivial | Milestone: | 0.22 |
| Component: | mythtv | Version: | 0.21-fixes |
| Severity: | low | Keywords: | |
| Cc: | Ticket locked: | no |
Description
Currently the logic for selecting for fast CMOV or slower CMOV (Netburst-based CPUs) is broken and appears to be assuming a slower CMOV and only enables fast_cmov when a CPU detection override is called for.
This could result in AVC CABAC decoding going slower than it should (from what I gather by reading piles of discussions from the ffmpeg mailing list).
Note this has nothing to do with those cheapie CPUs (*kof*C3*kof*) that don't support CMOV at all--that is being checked for elsewhere and looks correct enough.
Attachments (1)
Change History (6)
Changed 16 years ago by
| Attachment: | mythtv-0.21f-fast_cmov_fix.diff added |
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comment:1 Changed 16 years ago by
See also http://article.gmane.org/gmane.comp.video.mplayer.devel/40328 for the same issue for a different project (MPlayer) and a _very_ simple explanation.
comment:2 Changed 16 years ago by
| Owner: | changed from Isaac Richards to stuartm |
|---|---|
| Status: | new → accepted |
comment:3 Changed 16 years ago by
| Milestone: | 0.21.1 → 0.22 |
|---|---|
| Owner: | changed from stuartm to Janne Grunau |
the patch is wrong. $cpu is "generic" if it wasn't overriden.
I'll commit a proper fix soon.
comment:4 Changed 16 years ago by
comment:5 Changed 15 years ago by
| Resolution: | → fixed |
|---|---|
| Status: | accepted → closed |
Fixes selection of cmov/fast_cmov