Date: Thu, 01 Dec 2005 14:12:33 +1100 From: Michael Vince <mv@roq.com> To: =?ISO-8859-1?Q?Eirik_=D8verby?= <ltning@anduin.net> Cc: stable@freebsd.org Subject: Re: Reduced java/tomcat performance 6-beta3 -> 6-stable ? Message-ID: <438E6A21.3070705@roq.com> In-Reply-To: <9720F96D-A0F7-4639-8852-63A0F2C1FCDE@anduin.net> References: <93F6B911-8C64-4F5C-81F9-80EC271ED298@anduin.net> <84dead720511280545v2bc0bc35jd107da06b9a788cb@mail.gmail.com> <20187843-76FC-4EAB-AFF8-7493FB0C0077@anduin.net> <84dead720511280654j138635abgcb9cc0978e6c26b7@mail.gmail.com> <02757598-222D-408E-8B33-C2EE1E6E426E@anduin.net> <20051128211440.GB28963@xor.obsecurity.org> <3A601A32-94D1-49F6-AB06-ED54D50D4B6A@anduin.net> <9720F96D-A0F7-4639-8852-63A0F2C1FCDE@anduin.net>
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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. 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. 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. 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. 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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