Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: A second question ... Tablebases!

Author: Lars Bremer

Date: 12:24:52 01/11/04

Go up one level in this thread


On January 11, 2004 at 14:17:26, Eugene Nalimov wrote:

>On January 11, 2004 at 14:01:55, Lars Bremer wrote:
>
>>On January 10, 2004 at 16:22:25, Robert Hyatt wrote:
>>
>>>On January 10, 2004 at 12:13:20, Lars Bremer wrote:
>>>
>>>>On January 10, 2004 at 11:51:46, Robert Hyatt wrote:
>>>>
>>>>>On January 10, 2004 at 11:30:52, Lars Bremer wrote:
>>>>>
>>>>>>Hi,
>>>>>>
>>>>>>>I have to buy a new OS :-((
>>>>>>
>>>>>>Win2k does support HT. It handles HT as two different physical processors. WinXP
>>>>>>can handle these virtual processors.
>>>>>>
>>>>>>>The biggest wish is a good Service Pack for Windows NT4 (SP7) with USB, >Directx9
>>>>>>>and Hyperthreading support! That's all :-)
>>>>>>
>>>>>>It exists and is called Windows XP
>>>>>>
>>>>>>>BTW:
>>>>>>>Bob do you think that SCSI is better as S-ATA (interesting for me if I used on
>>>>>>>two harddisk 5-pieces for engine-engine matches with ponder = on on dual Xeon.
>>>>>>>After my first test it seems that S-ATA is just great for tablebases.
>>>>>>
>>>>>>Lol, SATA-drives are exactly the same as PATA-drives, there are no differences.
>>>>>>I count them twice, believe me.
>>>>>>Normally there is only a special chip at the drive's board to convert parallel
>>>>>>to serial.
>>>>>>
>>>>>>If you want to know which kind of drive is better to store and use tablebases,
>>>>>>you should read CSS 4/03, where I compared some different hard drives under this
>>>>>>point of view.
>>>>>>15k-SCSI was the best, but it was not as fast as one could think, and modern
>>>>>>ATA-drives are very fast too.
>>>>>
>>>>>SCSI drives offer far more than the IDE and IDE-followon SATA drives.
>>>>>
>>>>>(1) 320mb/sec burst transfers, double SATA, 2.5X IDE.
>>>>
>>>>You talking about the protocol, not about the drives. The fastest SCSI-drives
>>>>can transfer around 75 MByte/sec, the fastest IDE-drives are close to 60
>>>>MByte/sec now.
>>>
>>>We are talking two different numbers.  I'm talking peak burst transfer from
>>>on-board cache to main memory.  Not sustained data transfer rate for long
>>>reads.
>>
>>Yes, of course. But the peaks have nothing to do with the real life performance.
>>
>>>If you think your IDE drive is within 20% of a 15K scsi drive, we can run a
>>>benchmark to compare them. Every time I have done this, IDE simply gets
>>>blown out of the water...
>>
>>May be you ran the wrong benchmarks. We are talking about tablebases. And here
>>is the advantage of a SCSI drive not as high as the technical parameters like
>>seek time and transfer rate would suggest. I tested it with a complete set of
>>5-men-TBs. I tried following drives:
>>
>>drive			rpm	cache [kB]	seek time [ms]	transfer rate [Mbyte/s]
>>U320 Fujitsu MAS3735NP	15000	8192		4,4		70,8
>>UDMA6 Samsung SP1604N	7200	2048		10,8		43,5
>>UDMA5 Fuj. MPG3204AH-E	7200	2048		11,0		32,7
>>UDMA4 Maxtor 33073U4 	5400	512		13,4		21,7
>>
>>I let some programs solve some positions and picked the time. A typical result
>>was:
>>			depth 14	Matt in 13	Matt in 12
>>U320 Fujitsu MAS3735NP	00:37	        01:24	        04:45
>>UDMA6 Samsung SP1604N	00:46	        01:35	        05:08
>>UDMA5 Fuj. MPG3204AH-E	00:54	        01:45	        05:31
>>UDMA4 Maxtor 33073U4 	01:24	        01:45	        06:31
>>
>>this was only one program in one position (5R2/5br1/8/4b1B1/8/3k3K/8/8 b - -).
>>Not too impressive, the SCSI-rocket.
>>
>>
>>>And it doesn't totally hang the system while the
>>>drives are busy either.
>>>
>>>
>>>>
>>>>>(2) tagged command queueing
>>>>
>>>>tagged command queueing  is *not* an SCSI-feature. IBMs IDE hard disk drives can
>>>>do that since a lot of years. Unfortunatly there is no IDE-driver to handle
>>>>this. :)
>>>>
>>>>
>>>>>which offloads the "optimizing" stuff from the
>>>>>I/O request handler and lets the SCSI controller handle multiple requests in
>>>>>the best possible order, something a request handler can hardly do since disk
>>>>>drives like to "lie" about their geometry due to various compensation zones.
>>>>>
>>>>
>>>>>(3) run on a SCSI and IDE system side by side.  Do something HUGE in terms of
>>>>>I/O on both.  The scsi system will feel perfectly normal.  The IDE system
>>>>>will basically "freeze".
>>>>
>>>>It depends. In a server system with a lot of small I/Os, may be. In your
>>>>computerchess- and desktop-pc, nevermind.
>>>>
>>>>>There is little to recommend IDE or SATA except _price_.  That is where its
>>>>>only advantage is seen.
>>>>
>>>>So you must be deaf! I never want to have a 15k-SCSI under my desk :)
>>>
>>>I have 7 of them and they don't make much noise.  The Case fans are far
>>>noisier.  I can barely hear the drives.  In fact, I don't notice any
>>>difference in the 15K drives and the older 10K drives, I have both side-by-
>>>side.
>>
>>May be you are too old to hear the high frequent whistling of an 15k drive ;)
>>In fact you need a fan for SCSI drives. ATA-drives don't need an additional
>>cooling. And, your desk must vibrate when your 7 SCSI drives are seeking...
>>
>>
>>>
>>>>
>>>>>But I want performance.  And for endgame tables, the
>>>>>faster the better.
>>>>
>>>>So you did measure it? What is most important? latency, transfer rate, any
>>>>other?
>>>
>>>Latency _and_ transfer rate.  15K offers the best latency by a factor of 2.
>>>Transfer rate is next...  U320 SCSI wins there as well.
>>
>>Well, latency is not the only parameter to describe the seek time. The time to
>>move the heads between the tracks is a part of seek time too. I do not think
>>this seek time is the main important factor for TB-access. I tried it with a
>>test position with the samsung drive, once with acoustic management=fast (seek
>>time=10,8 ms) and once with acoustic = quiet (seek time = 12,3 ms). There is a
>>differenc around 10 percent. The time to solve some positions was nearly the
>>same...
>>
>>>>>15K drives are great, U320 15K drives are even better.
>>>>
>>>>If you use only one drive there is no difference in speed between U160 and U320.
>>>
>>>I disagree, although I have not specifically tested that.  But U320 disks
>>>are out-performing U160 disks in two machines I have sitting side by side.
>>>IE just doing a disk-to-disk copy of a large file...
>>
>>So you use U320 drives with an U160-controller? Come on. If the drives are
>>different, your "out-performing" says nothing. But this is very off topic.
>>
>>greets
>>
>>Lars
>
>I have one system with SCSI U320 controller and two hard drives plugged in --
>U160 and U320. According to specifications those drives have similar seek times.
>U320 drive consistently outperforms U160 one in disk-heavy activities (TB
>splitting, compression, copying, verification, etc.)

Ok ok, I believe you :) I did measure only once, it is a logn time ago with a
prototype of an U320-Controller and a maxtor drive with beta-firmware. I found
only very small differences.

btw: I am not sure that similiar drives have the same firmware in the U320 and
the U160 version. :)

greets, Lars


>
>Another good test is program start time in the presence of lot of TBs. I believe
>Bob reported *very* good start time for his system...
>
>Thanks,
>Eugene



This page took 0 seconds to execute

Last modified: Thu, 15 Apr 21 08:11:13 -0700

Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.