[PD] -rt startup flag ignored

[Edgar Berdahl]

Hi,

I believe that the -rt flag is still ignored in extended version 0.42.5. To debug this, I am using my own version of ps which lists the threads and also RTPRIO priorities:
ps -eLo pid,class,rtprio,ni,pri,pcpu,stat,comm --sort -rtprio

Depending on your kernel settings, it might be harder for you to verify this, but I imagine you might find in the source code where it parses "flags" in .pdextended that it simply doesn't check for -rt.

If I start pd with -rt specified neither in ~/.pdextended nor on the command line, I get these priorities:
  PID CLS RTPRIO  NI PRI %CPU STAT COMMAND
 1299 TS       -   0  19 19.8 RLl  pd
 1299 TS       -   0  19  0.0 SLl  pd
 1299 FF      57   -  97  2.1 SLl  pd
 1299 TS       -   0  19  0.0 SLl  pd

but if I start with -rt "flags" field of ~/.pdextended I get the same realtime priority for all the pd threads!
  PID CLS RTPRIO  NI PRI %CPU STAT COMMAND
 1263 TS       -   0  19 23.3 RLl  pd
 1263 TS       -   0  19  0.0 SLl  pd
 1263 FF      57   -  97  1.8 SLl  pd
 1263 TS       -   0  19  0.0 SLl  pd
(I even tried putting -rt in two different places in "flags")

However, if I start using -rt on the command line I get the following priorities, for which all of the pd threads have at least RTPRIO 6:
  PID CLS RTPRIO  NI PRI %CPU STAT COMMAND
 1237 FF       6   -  46 30.9 SLl  pd
 1237 FF       6   -  46  0.0 SLl  pd
 1237 FF      57   -  97  1.1 SLl  pd
 1237 FF       6   -  46  0.0 SLl  pd
and then I don't get dropouts anymore. So for me, it is essential to use this option.


For the time being, my workaround is simply to put this shell script in ~/bin to add -rt to the flags every time the user calls pd:
#!/bin/bash
#
# Shell script to make pd always start with -rt, no matter what
# the user types.
/usr/bin/pd -rt $*


Warm regards!
- Edgar

PS. See also:  http://lists.puredata.info/pipermail/pd-list/2006-08/041087.html
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