FreeBSD 9.1 vs CentOS 6.3

Daniel Bilik daniel.bilik at
Sat Mar 23 20:35:20 UTC 2013

On Fri, 22 Mar 2013 10:03:27 +0100
Davide D'Amico <davide.damico at> wrote:

> Hi, I'm doing performance tests on a DELL R720, follows dmesg:
> ...
> I will use this server as a mysql-5.6 dbserver so I have a root 
> partition using a hw raid1 and a /DATAZFS partition, follows
> configuration:
> ...

Well, it seems to be interesting coincidence... We've just finished
benchmarking MySQL with various (m)allocators. The goal was to test
tcmalloc, but when the system was up and running, we've taken the
opportunity to benchmark also other alternatives... including jemalloc.
All tests were performed on default MySQL 5.5.28 running on Debian Wheezy.
Between the tests nothing was touched on the machine or the system, just
allocators were changed (ie. mysqld restarted).

Results for different test modes are available here...

It seems there is notable performance penalty for read-only transactions
when MySQL is using jemalloc. The more concurrent threads are running, the
more is jemalloc losing to other allocators. The penalty is also there for
read-write transactions, but not that significant (error bars in the
histograms also show that results for read-write tests tend to be very
unstable). OTOH in non-transactional tests, jemalloc seems to be in par
with others, and under specific load can even outperform some of them.

In your original post, there is not mentioned in what mode you've performed
OLTP test, but according to numbers I suspect it was "complex", ie.
transactional. Can you repeat tests (both on CentOS and FreeBSD) with
--oltp-test-mode=nontrx and/or simple?

						Daniel Bilik

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