On 27 May 2009, at 11:00, Daniel Iliev wrote:
...
I'm afraid the common sense says disabling the "cpudetection" USE
flag could lead to the problem I described in my previous message.
Please, don't get me wrong - I'm not arguing and I've never tried to
build mplayer with EIS that is unsupported by the CPU. It may work if
the build system detects and corrects such errors when cpudetection is
disabled.
I think it shouldn't apply to mplayer, as explained by Volker earlier
in the thread. If a USE for an unsupported EIS is detected, the
mplayer build process will ignore it, and build without them. This is
because mplayer specifically is particularly clever about this,
apparently.
I personally set the correct EIS USE flags for my CPU globally and
disable the cpudetection flag.
Clearly this is the ideal way.
... I didn't suggest you this approach because I believe somewhere
in this
thread you mentioned you wanted to use the same settings on several
different systems.
Not necessarily, but I don't want to have to *think* too much about
hardware. I mean, I can safely set MMX because I know reasonably well
what it is, I remember when it came out, and I remember reading as the
next couple of subsequent generations of CPU were released that they
would continue to support it. I have a pretty good idea that MMX is
ubiquitous, and I imagine it to be supported even to the very latest
Intel CPUs (not sure about AMD?).
But I don't know what SSE is or SSSE (??) or any of the others, and I
don't really have any desire to know. Just so long as my server works
then I'm happy. I mean, I guess if I used Linux on the desktop then
performance might be more important to me, and it would behove me to
optimise each system. Or if my server carried a lot of load. But my
Linux boxes mostly don't - they sit in a corner & serve files by
Samba & email by IMAP and very little more.
mplayer is kinda an exceptional case for me, because I rip DVDs
to .mp4 format and then stream them across the network from the
fileserver to my PS3. When I rip them, the process runs circa 12 or 14
hours, so if I can shave 10% of this then that may be useful - the
movie may be ready to watch an hour earlier, and on some occasion I
may be glad of that.
So if I `flagedit media-video/mplayer mmx mmxext sse sse2 ssse3 3dnow
3dnowext` that gets me the best performance for mplayer without having
to think about it.
Of course, the amount of time I've spent on this thread, I could
perhaps have learned *exactly* what all these extended instruction
sets do, who designed them, whether they're cross-licensed between
manufacturers and what their prospects are for continued support in
the future. But I would personally find that very boring, and I am
much happier to have learned a little about how mplayer's build system
works and how Gentoo wraps that.
Stroller.
