On Dec 1, 2005, at 04:12 , Michael Vince wrote:
Some apps that use of frequent queries of the system time for
example MySQL are well known in FreeBSD to be slower then Linux
because its more expensive to call compared to Linux, maybe Tomcat
is also another such app this can also be double the case depending
on on your jsp and servlet code.
True, but on equal hardware it should perform equally.
If you are on good hardware, are using 6 and keep your systems time
updated via ntp you might want to try changing from
kern.timecounter.hardware: ACPI-fast to TSC(-100) and doing a
benchmark this has already proven to increase performance of MySQL
by a significantly amount.
I will try this, though it will not solve my original problem (and
the subject is somewhat misleading now, as this seems to be
independent of kernel revisions).
Also some new experimental low-precision time code has been added
to current source tree to see how much performance increases can be
gained, weirdly enough some people have argued against it for I
guess a wide range of reasons such as they just have crap hardware
and don't care about performance, don't like the extra maintenance
of code or just like Red Hat fanatics having an easy way to bad
mouth FreeBSD performance. I think most people would agree though
that it has to be done, or have to choose to believe FreeBSD isn't
about performance among other goals.
I will not join this discussion ;)
With 6 you can also use the new thr threading library, try your
libmap.conf to libthr for testing, for example
[/usr/local/jdk1.4.2/]
libpthread.so.2 libthr.so.2
libpthread.so libthr.so
I been doing some 'ab' testing libthr with Apache2 compiled for
worker MPM and have some really interesting differences on server
load, loads of about 40 for pthread and around 5 thr under certain
tests with ab with the exact same test.
Too bad this causes jdk1.5.0-amd64 to crash...
Application startup times were significantly reduced, but only the
times it actually managed to start without failing. Latest at the 2nd
or 3rd transaction Java coredumps. :(
And as current load testing is done without Apache in between, this
is moot..
/Eirik
Mike
Eirik Øverby wrote:
Update: The diff below was made after making sure both systems
are running the exact same kernel. Behavior is the same. Building
new kernels (6-STABLE) now to get out of the BETA stage.
/Eirik
On Nov 28, 2005, at 22:53 , Eirik Øverby wrote:
Firmware versions are equal. BIOS settings are equal.
However, a diff of the dmesgs show (apart from MAC address
differences):
30c30
< Timecounter "ACPI-safe" frequency 3579545 Hz quality 1000
---
> Timecounter "ACPI-fast" frequency 3579545 Hz quality 1000
What on earth is that all about? The "slow" box has the ACPI-
fast timecounter...
/Eirik
On Nov 28, 2005, at 22:14 , Kris Kennaway wrote:
On Mon, Nov 28, 2005 at 09:54:30PM +0100, Eirik ?verby wrote:
Hi,
I think I have found the culprit. There must be some sort of
difference between the machines after all (BIOS revision?),
because
while on one machine the interrupt rate for the bge card stays
very
low (2 to be exact) during maximum load, the other machine goes
beyond 1000 and keeps rising constantly. This might also
explain why
performance slowly degrades over time on that machine, and
response
times vary wildly, while the "fast" machine responds nicely within
1-2 seconds no matter the load and testing time.
I will have to investigate this more closely. Is there a way
to force
the NIC to polling mode (I'm assuming that is the difference,
an IRQ
rate of 2 is too low for a heavily loaded server if the NIC is
interrupt-driven)?
Anything else I could look at?
BIOS update.
Kris
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