Messages in this thread | | | Date | Tue, 20 Feb 2007 21:45:05 +0100 | From | bert hubert <> | Subject | Re: all syscalls initially taking 4usec on a P4? Re: nonblocking UDPv4 recvfrom() taking 4usec @ 3GHz? |
| |
On Tue, Feb 20, 2007 at 02:40:40PM -0500, Benjamin LaHaise wrote:
> Make sure your system is idle. Userspace bloat means that *lots* of idle > activity occurs in between timer ticks on recent distributions -- all those
You hit the nail on the head. I had previously measured with X shut down, but the effect didn't disappear.
With init=/bin/bash, recvfrom suddenly takes from 900nsec to 1.3usec, with only slight correlation between inter-call delay and cycles spent.
I'm investigating this further as it appears this has a real life effect on my P4 - a drastic one!
processor : 0 vendor_id : GenuineIntel cpu family : 15 model : 4 model name : Intel(R) Pentium(R) 4 CPU 3.00GHz stepping : 1 cpu MHz : 3000.131 cache size : 1024 KB fdiv_bug : no hlt_bug : no f00f_bug : no coma_bug : no fpu : yes fpu_exception : yes cpuid level : 5 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx constant_tsc pni monitor ds_cpl cid xtpr bogomips : 6003.91 clflush size : 64
Thanks for your help!
-- http://www.PowerDNS.com Open source, database driven DNS Software http://netherlabs.nl Open and Closed source services - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |