Re: idle priority scheduling broken in 7.0-BETA4

On Mon, 24 Dec 2007, Rene Ladan wrote:

> Peter Jeremy schreef:
>> In August, I reported that idprio was not working in -current.
>> Successive upgrades to 7.0-BETA2 and 7.0-BETA4, as well as switching
>> to ULE have not resolved the problem.
>>
>> The problem affects both boinc-einsteinathome and boinc-setiathome and
>> causes them to report "No heartbeat from core client for 31 sec -
>> exiting" and get repeatedly restarted.  The boinc compute modules
>> (einstein_at_home, seti_at_home etc) use a SysV SHM segment to exchange
>> heartbeats with the boinc core client.  The problem is that the core
>> client is not being scheduled whilst the compute module is running,
>> causing them to die.
>>
>> Previously, multiple idprio tasks were round-robined but it seems that
>> something has been changed and it appears that the last scheduled task
>> is now re-scheduled.
>>
>> Has anyone else seen this behaviour?
>>
> On my CURRENT 2007-12-23 dualcore (Intel T5600) i386 I get similar behaviour
> when using the ULE scheduler.  With the 4BSD scheduler priorities are sometimes
> wrong, but boinc tasks (einstein,seti,simap) run continuously until preempted,
> they are kept in memory.
>
> last pid:  8141;  load averages:  2.03,  2.14,  2.18    up 0+20:48:27  10:51:54
> 146 processes: 7 running, 120 sleeping, 19 waiting
> CPU states:     % user,     % nice,     % system,     % interrupt,     % idle
> Mem: 373M Active, 1040M Inact, 223M Wired, 17M Cache, 112M Buf, 349M Free
> Swap: 4062M Total, 4062M Free
>
>  PID USERNAME  PRI NICE   SIZE    RES STATE  C   TIME   WCPU COMMAND
> 7315 boinc     171  i31 65960K 64904K CPU1   1 187:57 62.89% {einstein_S5R3_4.
> 7859 boinc     171  i31 13680K 12552K RUN    0  71:31 60.16% {simap_5.10_i686-
> 7859 boinc      20  i31 13680K 12552K kserel 0  71:31 10.45% {simap_5.10_i686-
> 5168 boinc       8  i31 41960K 37564K nanslp 0 205:14  0.00% {initial thread}
> 5168 boinc       8   19 41960K 37564K nanslp 0 205:14  0.00% {setiathome-5.27.
> 7315 boinc      20  i31 65960K 64904K ksesig 0 187:57  0.00% {einstein_S5R3_4.
> 7315 boinc      20  i31 65960K 64904K kserel 0 187:57  0.00% {einstein_S5R3_4.
> 7859 boinc      20  i31 13680K 12552K ksesig 0  71:31  0.00% {simap_5.10_i686-
> 22403 boinc     171  i31  9572K  6700K select 1   0:32  0.00% boinc_client

Can you please try this experimental patch for ULE?  It re-enables the 
time slicing code for idle prio and realtime tasks that are not fifo.

Thanks,
Jeff

>
>
> Rene
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