Date: Thu, 30 Mar 2006 18:41:30 +0200 From: "Eric" <ericd@free.fr> To: <freebsd-smp@freebsd.org> Subject: Low perf with smp Message-ID: <009301c65418$cc029f30$65fd24c0@Eric>
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Mail NETvigieHi all, I buy a new DELL PowerEdge 1850 with Bi-Xeon 2.8GHZ/2*2MB Dual Core = 800FSB processor, 2Go DDR2 RAM, PERC4di RAID controller with 2 SCSI U320 = 15.000tpm 36Go hdd on RAID1. I install on it Freebsd 6.0, apache 2.2.0 and mysql 4.1.18 and compare = performance with : OLD PowerEDge with only simple Bi-Xeon 3.0 GHZ and freebsd 4.11. The test is simple mysql query done by php script. Result is that test is two time slower with freebsd 6.0 and dual-core = than with old server. I try with and without smp and threaded kernel and results are same. I came back to Generic kernel to see if it come from my kernel = configuration but result was same. I then though it come from server and try to upgrade an other one and = have same result. I then think it come from 6.0 and try with 6.1 beta4 and see same result I then downgrad to 4.11 without smp and then find good perfs. So I just add to 4.11 generic kernel :=20 options SMP # Symmetric MultiProcessor = Kernel options APIC_IO # Symmetric (APIC) I/O And then perf go back down from 30secondes to 54 sec. I search a lot on internet and try with this : sysctl = machdep.cpu_idle_hlt=3D0 But result is same. When doing whith smp top it's just as mysql have to wait to have cpu. = During 10,20 sec it just go to 2,4% then grow. Without smp it grow very = quickly. Does anyone know what's go wrong and what do I have to do to have same = perf with smp than without? Thanks, Eric.
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