FC4 kernel performance
davej at redhat.com
Tue Jun 21 18:42:20 UTC 2005
On Tue, Jun 21, 2005 at 02:17:59PM -0400, Malita, Florin wrote:
> On Tue, 2005-06-21 at 11:47 -0400, Dave Jones wrote:
> > Which is an apples to oranges comparison. 2.6.11-1.1369_FC4 is
> > actually based on 2.6.12rc6. I'll be interested in seeing results
> > rerun against this kernel.
> Back with some apples: http://lufs.sourceforge.net/unixbench.html
> Now I have:
> 1. Linux 2.6.12-rc6 (nodebug+p4+nose+nohm+lean): 355.7
> 2. Linux 188.8.131.52 (nodebug+p4+nose+nohm+lean): 345.8
> 3. Linux 2.6.11-1.1369_FC4 (nodebug+p4+nose+nohm+lean): 269.3
> 4. Linux 2.6.11-1.1369_FC4 (nodebug+p4+nose+ nohm): 253.1
> 5. Linux 2.6.11-1.1369_FC4 (nodebug+p4): 239.4
> 6. Linux 2.6.11-1.1369_FC4 (nodebug): 236.7
> 7: Linux 2.6.11-1.1369_FC4 (orig): 213.2
> 8: SunOS 5.11 (orig): 122.3
> (1, 2 & 3 here share the same configuration)
> So 2.6.12-rc6 is slightly better overall than 184.108.40.206 and still a lot
> faster than FC4 (especially in the syscall overhead & pipe throughput
Thanks, I'll take a look at this later.
> Am I correct in assuming the FC kernel doesn't use the vsyscall/sysenter
> mechanism thus taking a serious performance hit on P4s?
Correct. (Unless you have a CPU with NX).
I think we'd also be able to reenable sysenter if we booted with exec_sheild=0,
but currently we don't handle that case (we just always disable if no NX present)
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