Re: [tbench regression fixes]: digging out smelly deadmen.
From: Andrew Morton <akpm@linux-foundation.org>
Date: 2008-10-26 09:35:28
Also in:
lkml
On Sun, 26 Oct 2008 12:27:22 +0300 Evgeniy Polyakov [off-list ref] wrote:
Hi. On Sun, Oct 26, 2008 at 02:11:53AM -0700, Andrew Morton (akpm@linux-foundation.org) wrote:quoted
quoted
Andrew said recently: "dbench is pretty chaotic and it could be that a good change causes dbench to get worse. That's happened plenty of times in the past." So I'm not inclined to worry too much about dbench in any way shape or form.Well. If there is a consistent change in dbench throughput, it is important that we at least understand the reasons for it. But we don't necessarily want to optimise for dbench throughput.Sorry, but such excuses do not deserve to be said. No matter how ugly, wrong, unusual or whatever else you might say about some test, but it shows the problem, which has to be fixed.
Not necessarily. There are times when we have made changes which we knew full well reduced dbench's throughput, because we believed them to be of overall benefit. I referred to one of them above.
There is no 'dbench tune', there is fair number of problems, and at least several of them dbench already helped to narrow down and precisely locate. The same regressions were also observed in other benchmarks, originally reported before I started this thread.
You seem to be saying what I said.