linux-kernel - Re: SATA buffered read VERY slow (not raid, Promise TX300 card); 2.6.23.1(vanilla)

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date:	Thu, 03 Jan 2008 15:20:33 -0500
From:	Chuck Ebbert <cebbert@...hat.com>
To:	Linda Walsh <lkml@...nx.org>
CC:	LKML <linux-kernel@...r.kernel.org>
Subject: Re: SATA buffered read VERY slow (not raid, Promise TX300 card);
 2.6.23.1(vanilla)

On 12/30/2007 12:06 AM, Linda Walsh wrote:
> I needed to get a new hard disk for one of my systems and thought that
> it was about time to start going with SATA.
> 
> I picked up a Promise 4-Port Sata300-TX4 to go with a 750G
> Seagate SATA -- I'd had good luck with a Promise ATA100 (P)ATA
> and lower capacity Seagates and thought it would be a good combo.
> 
> Unfortunately, the *buffered* read performance is *horrible*!
> 
> I timed the new disk against a 400GB PATA and old 80MB/s SCSI-based
> 18.3G hard disk.  While the raw speed numbers are faster as expected,
> the linux-buffered read numbers are not good.
> 
> 
> sda=18.3G on 80MB/s SCSI
> sdb=the new 750GB on a 3Gb SATA w/NCQ.
> hdf=400GB PATA on an ATA100 Promise card
> 
> I used "dd" for my tests, reading 2GB on a quiescent machine
> that has 1GB of main memory.  Output was to dev null.  Input
> was from the device (not a partition or file), (/dev/sda, /dev/sdb
> and /dev/hdf).  BS=1M, Count=2k.  For the direct tests, I used
> the "iflag=direct" param.  No RAID or "volumes" are involved.
> 
> In each case, I took best run time out of 3 runs.
> 
> Direct read speeds (and cpu usage):
> dev   speed       cpu/real     %
> sda   60MB/s     0.51/35.84   1.44
> sdb   80MB/s     0.50/26.72   1.87
> hdf   69.4MB/s   0.51/30.92   1.68
> 
> 
> Buffered reads show the "bad news":
> dev   speed       cpu/real     %
> sda   59.9MB/s  20.80/35.86   58.03
> sdb   18.7MB/s  16.07/114.73  14.01  <-SATA extra badness
> hdf   69.8MB/s  17.37/30.76   56.48
> 
> I assume this isn't expected behavior.
> 

Try the PATA driver for the parallel ATA drive to see if it
has the same behavior.

Reboot before each test (or use drop_caches.)

hdparm should mostly work for reading drive settings but not for
writing them...
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/