[mythtv-users] Compelling reasons to go 64bit?

Yeechang Lee ylee at pobox.com
Thu Nov 30 06:41:29 UTC 2006


Chris Ribe <chrisribe at gmail.com> says:
> The EM64T is a strange beast in that regard.  It can do a reasonable
> impersonation of a dual core chip in 32bit mode, so switching to
> 64bit mode will effectively halve my processing power for certain
> applications.

Hmm. As implied in my original reply I haven't seen any detrimental
effects on MythTV from having gone 64-bit on my EMT64 box, but as
mentioned there were other changes that have obfuscated any attempts
at performance measurement. How might what you describe affect my
MythTV-related activities? If there are no MythTV-related effects, I
wouldn't care as this is a dedicated frontend/backend.

It sounds like you're talking about certain single-threaded
applications, while the developers have stated that MythTV's
components are highly multithreaded and can take good advanage of
Hyperthreading (as I've verified in person by temporarily turning this
off in the BIOS) and multicore/multiprocessor systems.

Now that I think about it, there *is* one bit of evidence of a
performance benefit from having gone 64-bit: top. According to top,
mythfrontend runs at about 30-70% (of half the Hyperthreaded
processor) CPU load, versus 50-80% in 32-bit. Same Nvidia video
driver, same MythTV release (recompiled in both cases with
--enable-proc-opt), 32-bit Fedora Core 4 versus 64-bt Fedora Core
6. Hardly conclusive, of course, but as mentioned above the absence of
problems is good enough for me.

-- 
Yeechang Lee <ylee at pobox.com> | +1 650 776 7763 | San Francisco CA US


More information about the mythtv-users mailing list