[mythtv-users] **Update - FIXED** mythbackend not responding -and even more weirdness

[Mark Knecht]

On 12/27/06, devsk <funtoos at yahoo.com> wrote:
>
> Mark,
>
> Did you file a bug yet? Filing a bug means that problem gets recorded and is
> searchable by others.

No bug reports files yet. I do file bug reports with Gentoo when I
have something repeatable. This one may be. I've gotten a little gun
shy with some of the responses I've received back for filing reports
so now I'm far more careful.

>
> Are you running ~ARCH with gentoo or stable?

As stable as possible on this machine.

>
> With dual core cpus, I have found that PREEMPT, SCHED_MC (multicore
> scheduler) and NUMA need to be off for stable operation. I only use
> Voluntary Kernel Preemption and Preempt the big kernel lock. And I have seen
> the strace magic happen on my machine before, so you are not alone....:-)

If that's the case then I probably could make changes. I have at least
PREEMPT and SCHED_MC on. I've never used NUMA. Isn't that specific to
specialized hardware? Anyway, it's not on that machine. Is this an
issue on all machines or only the backend?

Do you mean problems for Myth or problems in general? This P4HT has
been SMP for a long time but the only issue has been mythbackend. It's
been an issue over all SMP kernels I've run since about 2.6.14.

>
> I have been running myth on X2 3800+ for a while in SMP configuration and
> load both cores all the time without any freezing or hangs. I have had
> stable operation with last of the 2.6.17, 2.6.18 and now 2.6.19.1; all
> gentoo-sources patched for reiser4 and suspend2. I run my gentoo with
> ~amd64.

All machines here are Gentoo:

1) backend/frontend - P4HT - 2.6.17-gentoo-r2
2) frontend - AMD64 running 64-bit - mostly stable but ~amd64 for
audio apps. (proaudio overlay)
3) frontend - AMD64 running 32-bit - all stable. (proaudio overlay)
4) Two Pundit-R mythfrontends - Intel Celeron, ATI chipset & graphics

Thanks for the info. It's helpful.

Cheers,
Mark

>
> -devsk
>
>
> ----- Original Message ----
> From: Mark Knecht <markknecht at gmail.com>
> To: hah at alumni.rice.edu; Discussion about mythtv <mythtv-users at mythtv.org>
> Sent: Wednesday, December 27, 2006 9:37:05 AM
> Subject: Re: [mythtv-users] **Update - FIXED** mythbackend not responding
> -and even more weirdness
>
>
> On 12/27/06, Henry A Harper III <hah at alumni.rice.edu> wrote:
> >
> >
> > > -----Original Message-----
> > > From: mythtv-users-bounces at mythtv.org
> > > [mailto:mythtv-users-bounces at mythtv.org]On Behalf Of Mark Knecht
> > > Sent: Wednesday, December 27, 2006 9:48 AM
> > > To: Discussion about mythtv
> > > Cc: dusteur at excite.com
> > > Subject: Re: [mythtv-users] **Update - FIXED** mythbackend not
> > > responding -and even more weirdness
> > >
> > >
> > > On 12/27/06, Bill Arlofski <waa-mythtv at revpol.com> wrote:
> > > <SNIP>
> > > >
> > > > Does any of the burden of this problem fall on the mythtv devs? Is it
> a
> > > > programming issue with Mythtv and SMP? Is it an AMD Athlon64 X2 SMP
> > > > issue specific to the CPU I am using? Again, I do not know.
> > > >
> > > <SNIP>
> > >
> > > Interesting results. It might well be SMP related. I have a P4HT
> > > machine as the backend server and it's having similar problems.
> > >
> > > We are having a lot of problems with mythbackend just shutting off,
> > > but it seems to only shut off only when there are mythfrontend
> > > machines that are just finishing watching programs. Over the Christmas
> > > break we travelled for 4 days. mythbackend recorded everything
> > > correctly for about 40 hours of material. Lots to watch, so we started
> > > trying to do so. Yesterday mythbackend shut off 3 times. I'd restart
> > > the backend and it would happen again maybe 1-2 hours later.
> > >
> > > Thanks for the SMP idea. I'll look at that and report back.
> > >
> >
> > FYI, my 4600+ x2 w/ 2.6.17 SMP kernel in a FE/BE has been up 97 days with
> no
> > backend "weirdness" other than xbox360-caused upnp issues (just 100% core
> > usage, not unresponsive) until I went to newer svn head last week.
>
> Good to know and glad it's working for you. We're Gentoo here. HEre's
> what's installed on the backend machine:
>
> dragonfly ~ # eix -Ic mythtv
> [I] media-tv/mythtv (0.20_p11626): Homebrew PVR project
> [I] x11-themes/mythtv-themes (0.20): A collection of themes for the
> MythTV project.
> Found 2 matches.
> dragonfly ~ # uname -a
> Linux dragonfly 2.6.17-gentoo-r2 #4 SMP PREEMPT Fri Nov 24 14:20:30
> PST 2006 i686 Intel(R) Pentium(R) 4 CPU 3.00GHz GenuineIntel GNU/Linux
> dragonfly ~ #
>
> Note that this problem existed before on myth-0.18 and 0.19. It was
> not changed much by going to gcc-4.1.1. Pretty much the same level of
> problems.
>
> Here's an example of something I'm seeing in the log files this
> morning. I do NOT know if this is a reoccuring problem. It's jsut at
> the end of my log:
>
> [mpeg2video @ 0xb7345348]00 motion_type at 0 27
> [mpeg2video @ 0xb7345348]00 motion_type at 0 28
> [mpeg2video @ 0xb7345348]00 motion_type at 0 29
> [mpeg2video @ 0xb7345348]Warning MVs not available
> *** glibc detected *** /usr/bin/mythbackend: double free or corruption
> (fasttop): 0xa8605138 ***
> ======= Backtrace: =========
> /lib/libc.so.6[0xb5ea9bab]
> /lib/libc.so.6(__libc_free+0x79)[0xb5eab0e7]
> /usr/lib/gcc/i686-pc-linux-gnu/4.1.1/libstdc++.so.6(_ZdlPv+0x21)[0xb603a929]
> /usr/lib/libmythtv-0.20.so.0(_ZNSt6vectorIiSaIiEE13_M_insert_auxEN9__gnu_cxx17__normal_iteratorIPiS1_EERKi+0xfc)[0xb78a1da6]
> ======= Memory map: ========
> 08048000-0812a000 r-xp 00000000 03:08 296515     /usr/bin/mythbackend
> 0812a000-0812b000 rw-p 000e2000 03:08 296515     /usr/bin/mythbackend
> 0812b000-083cc000 rw-p 0812b000 00:00 0          [heap]
> a8400000-a8460000 rw-p a8400000 00:00 0
> a8460000-a8500000 ---p a8460000 00:00 0
> a8600000-a8644000 rw-p a8600000 00:00 0
> a8644000-a8700000 ---p a8644000 00:00 0
> a9000000-a9100000 rw-p a9000000 00:00 0
> a91f4000-a91f5000 ---p a91f4000 00:00 0
> a91f5000-a99f5000 rw-p a91f5000 00:00 0
> a99f5000-a99f6000 ---p a99f5000 00:00 0
>
> <SNIP>
> b7ef7000-b7ef8000 rw-p 00000000 03:08 705168
> /usr/lib/mythtv/filters/libbobdeint.so
> b7ef8000-b7efa000 r-xp 00000000 03:08 705149
> /usr/lib/mythtv/filters/libadjust.so
> b7efa000-b7efb000 rw-p 00001000 03:08 705149
> /usr/lib/mythtv/filters/libadjust.so
> b7efb000-b7f03000 r-xp 00000000 03:08 753706     /lib/libnss_files-2.4.so
> b7f03000-b7f05000 rw-p 00007000 03:08 753706     /lib/libnss_files-2.4.so
> b7f05000-b7f0e000 r-xp 00000000 03:08 522754
> /usr/qt/3/plugins/sqldrivers/libqsqlmysql.so
> b7f0e000-b7f0f000 rw-p 00009000 03:08 522754
> /usr/qt/3/plugins/sqldrivers/libqsqlmysql.so
> b7f0f000-b7f10000 rw-p b7f0f000 00:00 0
> b7f10000-b7f29000 r-xp 00000000 03:08 753640     /lib/ld-2.4.so
> b7f29000-b7f2a000 r--p 00019000 03:08 753640     /lib/ld-2.4.so
> b7f2a000-b7f2b000 rw-p 0001a000 03:08 753640     /lib/ld-2.4.so
> bf9cd000-bf9e3000 rw-p bf9cd000 00:00 0          [stack]
> ffffe000-fffff000 ---p 00000000 00:00 0          [vdso]
> 0: start_time: 0.036 duration: 151.976
> 1: start_time: 0.026 duration: 151.954
> stream: start_time: 0.289 duration: 1688.731 bitrate=5193 kb/s
> [mpeg2video @ 0xb7345348]ac-tex damaged at 22 6
> 0: start_time: 0.036 duration: 232.471
> 1: start_time: 0.026 duration: 232.444
> stream: start_time: 0.289 duration: 2583.125 bitrate=7217 kb/s
> Starting up as the master server.
>
>
> I don't even know if the Myth developers read this list or want this
> info. Maybe pass it upstream through Gentoo?
>
> Thanks,
> Mark
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