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slowdown with new scheduler.

DISCUSSION Dave Jones 4 participants 6 messages Jan 14, 2002

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Dave Jones

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#0 lore raw

Hi Ingo,
After adding H7 to 2.4.18pre3, I noticed that kernel compiles
on one of my test boxes got much slower.
Uniprocessor system (Cyrix 3) building a 2.4.18pre3 tree, with the same .config, and a distclean before starting the compile.

2.4.18pre3 13.38s
2.4.18pre+H7 17.53s

I see similar slowdown when running H7 on 2.5 on this box.

regards,
Dave.

Signature · 2 lines
Dave Jones.                    http://www.codemonkey.org.uk
SuSE Labs.
#1 lore raw
Quoted 10 lines · Dave Jones

Hi Ingo,
After adding H7 to 2.4.18pre3, I noticed that kernel compiles
on one of my test boxes got much slower.
Uniprocessor system (Cyrix 3) building a 2.4.18pre3 tree, with the same .config, and a distclean before starting the compile.

2.4.18pre3 13.38s
2.4.18pre+H7 17.53s

I see similar slowdown when running H7 on 2.5 on this box.

Another anecdote: my dnetc client (niced at 19) scores went from 4.2 Mkeys/s to 4.0 Mkeys/s. (Athlon 1.2GHz tbird).

Signature · 3 lines
- Antony Suter  ([email protected])  "Examiner" 
openpgp:7916EE67
- "Savahnah River. K Reactor. 1968. It was a very good year."
#2 lore raw
In reply to Dave Jones
Quoted 7 lines · Dave Jones

After adding H7 to 2.4.18pre3, I noticed that kernel compiles
on one of my test boxes got much slower.
Uniprocessor system (Cyrix 3) building a 2.4.18pre3 tree, with the same .config, and a distclean before starting the compile.

2.4.18pre3 13.38s
2.4.18pre+H7 17.53s

I did the same; same config, fresh tree, reboot between the test. The machine is a (single-processor) AMD K6-2/400 with 256 MB RAM. Here are the results:

2.4.18-pre3 real 7m55.243s

			    user    6m34.080s
			    sys     0m27.610s

2.4.18-pre+H7 real 7m35.962s

			    user    6m34.270s
			    sys     0m27.700s

2.4.18-pre3-ac2 real 7m39.203s

			    user    6m34.110s
			    sys     0m28.740s

Ingo's scheduler rocks, it runs like hell (and is absolutely stable here) ;)

Signature · 1 line
# Heinz Diehl, 68259 Mannheim, Germany
author
#3 lore raw
In reply to Dave Jones
Quoted 5 lines · Heinz Diehl

I did the same; same config, fresh tree, reboot between the test. The machine is a (single-processor) AMD K6-2/400 with 256 MB RAM. Here are the results:
... <deletia>
Ingo's scheduler rocks, it runs like hell (and is absolutely stable here) ;)

The issue seems to be when a process like dnetc is running (which runs at +19 iirc), it seems to be getting scheduled way too often.

Signature · 2 lines
| Dave Jones.        http://www.codemonkey.org.uk
| SuSE Labs
#4 lore raw
In reply to Dave Jones
Quoted 4 lines · Heinz Diehl

2.4.18-pre3 real 7m55.243s

			    user    6m34.080s
			    sys     0m27.610s
Quoted 8 lines

2.4.18-pre+H7 real 7m35.962s

			    user    6m34.270s
			    sys     0m27.700s

2.4.18-pre3-ac2 real 7m39.203s

			    user    6m34.110s
			    sys     0m28.740s

2.4.18-pre3+H7+preempt-rml real 6m58.983s
user 6m34.500s
sys 0m27.820s

:))

Signature · 1 line
# Heinz Diehl, 68259 Mannheim, Germany
#5 lore raw
In reply to Dave Jones
Quoted 17 lines · Heinz Diehl
Quoted 4 lines · Heinz Diehl

2.4.18-pre3 real 7m55.243s

			    user    6m34.080s
			    sys     0m27.610s
Quoted 8 lines

2.4.18-pre+H7 real 7m35.962s

			    user    6m34.270s
			    sys     0m27.700s

2.4.18-pre3-ac2 real 7m39.203s

			    user    6m34.110s
			    sys     0m28.740s

2.4.18-pre3+H7+preempt-rml real 6m58.983s

Review

Quoted 2 lines
(quoted diff) +0 -0
 			    user    6m34.500s
 			    sys     0m27.820s

That sounds very good! But what about the VM code? Is the VM in 2.4.18-pre3+H7 as good as in 2.4.18-pre2aa2?