On 1/28/11 8:15 AM, Stefan Lambrev wrote:
The overhead comes from badly written software.
This software is optimized for linux and you have to optimize it for freebsd,
then you will have the same overhead.
All those *popular* benchmarks like hping, iperf, netperf have some strange
optimizations for linux - we call them linuxism.
Just search the archives - I'm pretty sure patches are flying around.
He wants to know why the freeBSD driver spends 8 x as much time on
each interrupt.
there are of course several possible answers, including:
1/ Sometimes BSD and Linux report things differently. Linux may or may not
account for the lowest level interrupt tie the same as BSD
2/ the BSD driver for that chip may be badly written, or may
be doing more or different work for some reason
3/ the FreeBSD interrupt code may be misconfigured for that driver.
or maybe combinations...
there are profiling tools that you may decide to run.
Julian
On Jan 28, 2011, at 6:10 PM, Slawa Olhovchenkov wrote:
On Fri, Jan 28, 2011 at 06:03:15PM +0200, Stefan Lambrev wrote:
Do the test with netblast ;)
Most perf tools are written badly and for Linux.
In our internal test netblast running on freebsd outperform everything else.
I don't speak about bad performance.
I speak about overhead.
Linux: overhead 7% for 56K int/s
FreeBSD: overhead 59% for 14K int/s
For processing 1/4 interrupts FreeBSD need 8x CPU.
P.S. - /usr/src/tools/tools/netrate/netblast - we have tested little more
expensive card - em/igb and bce.
On Jan 28, 2011, at 4:33 PM, Slawa Olhovchenkov wrote:
I test network performance and found some strange result -- on the
same hardware Linux more then 10x used CPU resources for interrupt
processing.
FreeBSD system utilise 70% CPU (32% idle, 59% interrupt, 9% sys) and
network card generate 14K-18K interrupt per second.
Linux system utilise 20% CPU (80% idle, 13% system, 3% hiq, 4% siq)
and network card generate 56K interrupt per second.
I used 'netperf -H host -t UDP_STREAM -l 60 -C -c -- -m 8972 -s
128K -S 128K' for generate network traffic.
NIC:
re0:<RealTek 8169SC/8110SC Single-chip Gigabit Ethernet> port 0x4000-0x40ff
mem 0xf0100000-0xf01000ff irq 19 at device 4.0 on pci11
re0: Chip rev. 0x18000000
re0: MAC rev. 0x00000000
miibus0:<MII bus> on re0
rgephy0:<RTL8169S/8110S/8211B media interface> PHY 1 on miibus0
CPU:
CPU: Intel(R) Celeron(R) CPU 420 @ 1.60GHz (1596.05-MHz K8-class CPU)
Origin = "GenuineIntel" Id = 0x10661 Family = 6 Model = 16
Stepping = 1
Features=0xafebfbff<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,TM,PBE>
Features2=0xe31d<SSE3,DTES64,MON,DS_CPL,TM2,SSSE3,CX16,xTPR,PDCM>
AMD Features=0x20100800<SYSCALL,NX,LM>
AMD Features2=0x1<LAHF>
TSC: P-state invariant
RAM: one DDR2-667 DIMM.
OS: 8.2-RC2, amd64
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--
Best Wishes,
Stefan Lambrev
ICQ# 24134177
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--
Best Wishes,
Stefan Lambrev
ICQ# 24134177
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