Date: Sun, 23 May 2004 11:04:42 -0700 From: JG <amd64list@jpgsworld.com> To: freebsd-threads@freebsd.org Subject: Re: Why is MySQL nearly twice as fast on Linux? Message-ID: <5.2.0.9.2.20040523104834.01465598@mail.ojoink.com> In-Reply-To: <40B0E391.4000504@he.iki.fi> References: <5.2.0.9.2.20040523102747.015557e8@mail.ojoink.com> <5.2.0.9.2.20040523090659.01628af8@mail.ojoink.com> <5.2.0.9.2.20040522135338.0158cc50@mail.ojoink.com> <5.2.0.9.2.20040522100318.01598f50@mail.ojoink.com> <5.2.0.9.2.20040522052606.0156fd70@mail.ojoink.com> <5.2.0.9.2.20040521154458.01627688@127.0.0.1> <5.2.0.9.2.20040521154458.01627688@127.0.0.1> <5.2.0.9.2.20040522052606.0156fd70@mail.ojoink.com> <5.2.0.9.2.20040522100318.01598f50@mail.ojoink.com> <5.2.0.9.2.20040522135338.0158cc50@mail.ojoink.com> <5.2.0.9.2.20040523090659.01628af8@mail.ojoink.com> <5.2.0.9.2.20040523102747.015557e8@mail.ojoink.com>
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At 08:46 PM 5/23/2004 +0300, you wrote: >JG wrote: > >> >>You mean where I have the 3 instances of mysqld running in top? You have= =20 >>~30 instances? >I=B4m running the supersmack with $1=3D30. (For those reading this thread who have not looked at the super-smack=20 source code, which I'm sure most have not, what Pete means by $1 is the number of=20 simultaneous supersmack client connections to run, even though it would be $2 from shell ie: super-smack smackfile-to-run clients rounds-per-client) Anyway Pete, I am running the supersmack with 30 clients as well. But that isn't what I asked you. I have 30 supersmack clients running in top -H when the test is running (if= =20 I ran it with 30 clients anyway). What I don't have is 30 mysqld instances (I had 3, as shown), and that is=20 what you made it sound like you had. You said: "You seem to have a very small number of active threads. When I tried=20 supersmack on fairly old machine (800MHz dual pentium) I get ~30 active=20 mysql threads using CPU between 1.5% and 3.5%." So if this is not the case, please clarify. Or better... post your top -H while tests are running as well as the=20 super-smack command you ran. >>I know that this FreeBSD/AMD64 reports that it is using ACPI... how do I= =20 >>find out if its using timecounters, or using them properly? >kern.timecounter.hardware: ACPI-fast > >But I'm suspecting that the system call overhead between Linux and freebsd= =20 >differs enough to cause the results. If anything can be done about it, I=20 >don=B4t know. $ sysctl -a | grep 'ACPI' kern.timecounter.hardware: ACPI-fast kern.timecounter.choice: TSC(800) ACPI-fast(1000) i8254(0) dummy(-1000000) Looks like I'm ok there (on FreeBSD/AMD64). - Jeremy
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