Re: 2.5.38-mm2 dbench $N times

[Andrew Morton]

William Lee Irwin III wrote:
> 
> William Lee Irwin III wrote:
> >> Taken on 32x/32G NUMA-Q:
> >> Throughput 67.3949 MB/sec (NB=84.2436 MB/sec  673.949 MBit/sec)  16 procs
> >> dbench 16  11.72s user 122.21s system 422% cpu 31.733 total
> 
> On Tue, Sep 24, 2002 at 10:47:30AM -0700, Andrew Morton wrote:
> > Taken on 2x/0.8G el-scruffo PC:
> > Throughput 135.02 MB/sec (NB=168.775 MB/sec  1350.2 MBit/sec)
> > ./dbench 16  12.11s user 16.29s system 181% cpu 15.646 total
> > What's up with that?
> 
> Not sure. This is boot bay SCSI crud, but single-disk FC looks
> *worse* for no obvious reason. Multiple disk tests do much better
> (about matching the el-scruffo PC numbers above).
> 

dbench 16 on that sort of machine is a memory bandwidth test.
And a dcache lock exerciser.  It basically doesn't touch the
disk.  Something very bad is happening.

Anton can get 3000 MByte/sec ;)