Netbench results on a linux 4-way system
Goetz Rieger
goetz.rieger at suse.de
Thu Aug 1 01:00:15 GMT 2002
Hey Andrew,
On Wed, 31 Jul 2002 12:56:04 -0500
Andrew Theurer <habanero at us.ibm.com> wrote:
great stuff. As you can think, I have never got the chance to run "real"
netbench-runs. So I am not very familiar with interpreting the results....
Could you publish more data, like the plot throughput against clients?
Any performance data on Samba/Linux is relevant. ;-)
Regards,
Goetz
> I though I'd share some NetBench results on one of our servers.
>
> Server:
> 4 x 1.5 GHz P4, 256K L3, 32MB L4, 2 GB memory
> 4 x 1Gbps acenic ethernet
> 14 SCSI disks in hardware RAID1 with 128 MB writeback NVRAM
> SuSE 8.0, 2.4.18 kernel
> Samba 2.2.3a
> Ext3 fs
>
> Clients:
> 48 x 866 MHz PIII running Windows 2000
>
> Results:
>
> Baseline 576 Mbps
> ext3 data=writeback 623 Mbps
> samba smblog=1 673 Mbps
> sendfile/zerocopy 801 Mbps
> O(1) scheduler 809 Mbps
> Evenly affined IRQs 800 Mbps *needed to get process affinity correct
> Process affinity 848 Mbps
> /proc/sys/net/hll=764 853 Mbps
> case sens enforced 895 Mbps
> samba spinlocks 912 Mbps
> dcache read copy update 923 Mbps (also had 5% idle time)
>
> I have also achieved 1002 Mbps with ext2.
>
> Some other things I think may be worth investigating:
>
> gettimeofday(). Samba calls this a lot, one for every reply I think, to
> check for connection timeout. This means we go into kernel mode every
> single time we call this, something I'd like to avoid. And I also don't
> think we need the resolution of gettimeofday for this. How about some
> sort of timer in samba with a 1 second granularity? I admit I have not
> thought about how to do this, but there's gotta be a way.
>
> locking for the samba db. Spin locks got us a little better than
> flocks, but again I'd rather not go into kernel mode every time. Has
> anyone considered using Rusty Russell's futexes for this?
>
> Hyperthreading. With 2 physical processors, I can get 25% better
> results!!! with 4 physical processors, I only get 2% better. I may be
> running into other bottlenecks on the 4 physical/8 logical CPU case, so
> I hope there is room for improvement. However there are probably a lot
> more 2-way P4 systems out there than 4-way, so I bet this could really
> benefit a lot of people out there.
>
> Anyway, I have a lot of analysis data (kernel profiles mostly) that goes
> along with this stuff if anyone is interested in looking at it My
> intention was to make some sort of article out of this, so I wanted to
> get some feedback from this list. Is this stuff interesting or relevant
> to anyone out there? What else would you like to see in terms of samba
> on linux performance?
>
> Thanks,
>
> Andrew Theurer
>
>
>
>
>
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