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Date:      Sat, 11 Oct 2003 09:45:18 -0400
From:      "Christopher M. Sedore" <cmsedore@maxwell.syr.edu>
To:        <freebsd-threads@freebsd.org>
Subject:   odd problem(s) with libthr and libkse
Message-ID:  <32A8B2CB12BFC84D8D11D872C787AA9A515CD3@EXCHANGE.forest.maxwell.syr.edu>

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I have a multithreaded program that I've built to run under libc_r, =
libthr, and libkse.  I use the libc_r build for debugging and the others =
for actual work (the program is disk/network io intensive and I want the =
disk io concurrency from thr or kse).
=20
Anyway, here is the issue I'm seeing.  It may be the same or a related =
problem for both, or may not be.
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When running under libthr, everything works fine for an indeterminate =
period, usually between 10 seconds and 30 minutes.  Eventually, all =
program function stops.  If I watch in top, threads get stuck in =
"sigwai".  First one, then a couple, then all. =20
=20
When running under kse, the program pauses periodically.  I have one =
thread that prints out a heartbeat once per second, and prints debug =
info.  I get pauses of up to 5 seconds between my heartbeat:
=20
8 per sec (40/5) - 3739 total, 6047 pce active
6 per sec (32/5) - 3722 total
timer 1065864344
timer 1065864347
timer 1065864348
7 per sec (38/5) - 3777 total, 6034 pce active
7 per sec (39/5) - 3761 total
timer 1065864350
timer 1065864351
accepted on 14
accepted on 15
timer 1065864353
4 per sec (20/5) - 3797 total, 6058 pce active
6 per sec (30/5) - 3791 total
timer 1065864354
timer 1065864355
timer 1065864357

(note skips from 1065864348 to 350, 351 to 353, 355 to 357)
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When the pauses occur, network traffic dips to nearly nothing:  Overall =
program performance with libkse is about 25-50% of what it is under =
libthr (when working) or ~30-60% of libc_r.
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I have no problems when running under libc_r.  Any suggestions to debug =
this?
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I'm running 5.1-CURRENT-20030917-JPSNAP.
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Thanks,
=20
-Chris
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