From: Nick Piggin <piggin@cyberone.com.au>
To: Andrew Morton <akpm@osdl.org>
Cc: Con Kolivas <kernel@kolivas.org>,
linux-kernel@vger.kernel.org, lse-tech@lists.sourceforge.net
Subject: Re: [PATCH]O18.1int
Date: Sat, 23 Aug 2003 19:49:50 +1000 [thread overview]
Message-ID: <3F4738BE.6060007@cyberone.com.au> (raw)
In-Reply-To: <20030823023231.6d0c8af3.akpm@osdl.org>
Andrew Morton wrote:
>We have a problem. See the this analysis from Steve Pratt.
>
>
>Steven Pratt <slpratt@austin.ibm.com> wrote:
>
>>Mark Peloquin wrote:
>>
>>
>>>Been awhile since results where posted, therefore this is a little long.
>>>
>>>
>>>Nightly Regression Summary for 2.6.0-test3 vs 2.6.0-test3-mm3
>>>
>>>Benchmark Pass/Fail Improvements Regressions
>>>Results Results Summary
>>>--------------- --------- ------------ -----------
>>>----------- ----------- -------
>>>dbench.ext2 P N N 2.6.0-test3
>>>2.6.0-test3-mm3 report
>>>dbench.ext3 P N Y 2.6.0-test3
>>>2.6.0-test3-mm3 report
>>>
>>The ext3 dbench regression is very significant for multi threaded 193 ->
>>118. Looks like this regression first showed up in mm1 and does not
>>exist in any of the bk trees.
>>
>>http://ltcperf.ncsa.uiuc.edu/data/history-graphs/dbench.ext3.throughput.plot.16.png
>>
>>
>>>volanomark P N Y 2.6.0-test3
>>>2.6.0-test3-mm3 report
>>>
>>Volanomark is significant as well. 10% drop in mm tree. This one also
>>appeared to show up in mm1 although it was a 14% drop then so mm3
>>actually looks a little better. There were build errors on mm2 run so I
>>don't have that data at this time.
>>Following link illustrates the drop in mm tree for volanomark.
>>
>>http://ltcperf.ncsa.uiuc.edu/data/history-graphs/volanomark.throughput.plot.1.png
>>
>>
>>SpecJBB2000 for high warehouses also took a bit hit. Probably the same
>>root cause as volanomark.
>>Here is the history plot for the 19 warehouse run.
>>
>>http://ltcperf.ncsa.uiuc.edu/data/history-graphs/specjbb.results.avg.plot.19.png
>>
>>Huge spike in idle time.
>>http://ltcperf.ncsa.uiuc.edu/data/history-graphs/specjbb.utilization.idle.avg.plot.19.png
>>
>>
>>>http://ltcperf.ncsa.uiuc.edu/data/2.6.0-test3-mm3/2.6.0-test3-vs-2.6.0-test3-mm3/
>>>
>>>
>
>Those graphs are woeful.
>
Aren't they.
>
>Steve has done some preliminary testing which indicates that the volanomark
>and specjbb regressions are due to the CPU scheduler changes.
>
>I have verifed that the ext3 regression is mostly due to setting
>PF_SYNCWRITE on kjournald. I/O scheduler stuff. I don't know why, but
>that patch obviously bites the dust. There is still a 10-15% regression on
>dbench 16 on my 4x Xeon which is due to the CPU scheduler patches.
>
Thats fine. I never measured any improvement with it. Its sad that
that it didn't go as I hoped, but that probably tells you I don't
know enough about how journalling works.
>
>It's good that the reaim regression mostly went away, but it would be nice
>to know why. When I was looking into the reaim problem it appeared that
>setting TIMESLICE_GRANULARITY to MAX_TIMESLICE made no difference, but more
>careful testing is needed on this.
>
>There really is no point in proceeding with this fine tuning activity when
>we have these large and not understood regressions floating about.
>
I think changes in the CPU scheduler cause butterflies to flap their
wings or what have you. Good luck pinning it down.
>
>I suggest that what we need to do is to await some more complete testing of
>the CPU scheduler patch alone from Steve and co. If it is fully confirmed
>that the CPU scheduler changes are the culprit we need to either fix it or
>go back to square one and start again with more careful testing and a less
>ambitious set of changes.
>
>It could be that we're looking at some sort of tradeoff here, and we're
>already too far over to one side. I don't know.
>
>It might help if you or a buddy could get set up with volanomark on an OSDL
>4-or-8-way so that you can more closely track the effect of your changes on
>such benchmarks.
>
I think you'd be wasting your time until the interactivity side of
things is working better. Unless Con has a smaller set of undisputed
improvements to test with.
next prev parent reply other threads:[~2003-08-23 9:50 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-08-23 5:55 [PATCH]O18.1int Con Kolivas
2003-08-23 9:08 ` [PATCH]O18.1int Thomas Schlichter
2003-08-23 9:18 ` [PATCH]O18.1int Nick Piggin
2003-08-23 12:22 ` [PATCH]O18.1int Con Kolivas
2003-08-23 12:21 ` [PATCH]O18.1int Con Kolivas
2003-08-23 9:32 ` [PATCH]O18.1int Andrew Morton
2003-08-23 9:49 ` Nick Piggin [this message]
2003-08-23 16:58 ` [PATCH]O18.1int Con Kolivas
2003-08-23 21:49 ` [PATCH]O18.1int Andrew Morton
2003-08-24 2:46 ` [PATCH]O18.1int Con Kolivas
2003-08-23 13:29 ` [PATCH]O18.1int Con Kolivas
2003-08-25 9:24 ` [PATCH]O18.1int Måns Rullgård
2003-08-25 9:42 ` [PATCH]O18.1int Alex Riesen
2003-08-25 10:16 ` [PATCH]O18.1int Con Kolivas
2003-08-25 10:21 ` [PATCH]O18.1int Alex Riesen
2003-08-25 21:02 ` [PATCH]O18.1int Alex Riesen
2003-08-25 22:48 ` [PATCH]O18.1int Con Kolivas
2003-08-25 23:00 ` [PATCH]O18.1int Alex Riesen
2003-08-26 22:03 ` [PATCH]O18.1int Alex Riesen
2003-08-25 10:34 ` [PATCH]O18.1int Måns Rullgård
2003-08-25 10:50 ` [PATCH]O18.1int Con Kolivas
2003-08-25 11:15 ` [PATCH]O18.1int Måns Rullgård
2003-08-25 11:37 ` [PATCH]O18.1int Con Kolivas
2003-08-25 11:58 ` [PATCH]O18.1int Måns Rullgård
2003-08-25 12:28 ` [PATCH]O18.1int Con Kolivas
2003-08-25 12:49 ` [PATCH]O18.1int Måns Rullgård
2003-08-25 13:32 ` [PATCH]O18.1int Con Kolivas
2003-08-25 10:17 ` [PATCH]O18.1int Måns Rullgård
2003-08-25 10:34 ` [PATCH]O18.1int Alex Riesen
2003-08-25 11:23 ` [PATCH]O18.1int Måns Rullgård
2003-08-25 10:48 ` [PATCH]O18.1int Con Kolivas
[not found] ` <3F49E482.7030902@cyberone.com.au>
[not found] ` <20030825102933.GA14552@Synopsys.COM>
2003-08-26 22:20 ` [PATCH]O18.1int Alex Riesen
2003-08-27 2:26 ` [PATCH]O18.1int Nick Piggin
2003-08-23 22:03 [PATCH]O18.1int Voluspa
2003-08-24 4:04 ` [PATCH]O18.1int Con Kolivas
2003-08-28 12:23 [PATCH]O18.1int Guillaume Chazarain
2003-08-28 13:43 [PATCH]O18.1int Guillaume Chazarain
2003-08-28 13:58 ` [PATCH]O18.1int Nick Piggin
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=3F4738BE.6060007@cyberone.com.au \
--to=piggin@cyberone.com.au \
--cc=akpm@osdl.org \
--cc=kernel@kolivas.org \
--cc=linux-kernel@vger.kernel.org \
--cc=lse-tech@lists.sourceforge.net \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).