Messages in this thread |  | | | Date | Tue, 18 Dec 2001 18:42:49 +0100 (CET) | | From | Gérard Roudier <> | | Subject | Re: Poor performance during disk writes |
| |
On Tue, 18 Dec 2001, Andre Hedrick wrote:
> File './Bonnie.2276', size: 1073741824, volumes: 1 > Writing with putc()... done: 72692 kB/s 83.7 %CPU > Rewriting... done: 25355 kB/s 12.0 %CPU > Writing intelligently...done: 103022 kB/s 40.5 %CPU > Reading with getc()... done: 37188 kB/s 67.5 %CPU > Reading intelligently...done: 40809 kB/s 11.4 %CPU > Seeker 2...Seeker 1...Seeker 3...start 'em...done...done...done... > ---Sequential Output (nosync)--- ---Sequential Input-- --Rnd Seek- > -Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --04k (03)- > Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU > 1*1024 72692 83.7 103022 40.5 25355 12.0 37188 67.5 40809 11.4 382.1 2.4 > > Maybe this is the kind of performance you want out your ATA subsystem. > Maybe if I could get a patch in to the kernels we could all have stable > and fast IO.
I rather see lots of wasting rather than performance, here. Bonnie says that your subsystem can sustain 103 MB/s write but only 41 MB/s read. This looks about 60% throughput wasted for read.
Note that if you intend to use it only for write-only applications, performance are not that bad, even if just dropping the data on the floor would give you infinite throughput without any difference in functionnality. :-)
Gérard Roudier Not CEO, not President of anything.
> Regards, > > > Andre Hedrick > CEO/President, LAD Storage Consulting Group > Linux ATA Development > Linux Disk Certification Project
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
|  |