Re: 2.5.38-mm2 dbench $N times

Andrew Morton
2002-09-25T00:26:32Z

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 ;)