Date: Wed, 27 Dec 1995 16:46:23 +0100 From: se@zpr.uni-koeln.de (Stefan Esser) To: Joe Greco <jgreco@brasil.moneng.mei.com> Cc: freebsd-hackers@freebsd.org Subject: Re: iostat and msps Message-ID: <199512271546.AA16282@Sysiphos> In-Reply-To: Joe Greco <jgreco@brasil.moneng.mei.com> "Re: iostat and msps" (Dec 25, 14:34)
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On Dec 25, 14:34, Joe Greco wrote: } Subject: Re: iostat and msps } Maybe the inaccurate count is better than nothing at all. Solaris does a } convincing attempt at gathering statistics on SCSI disks, and even if it is } not 100% accurate, it helps an administrator locate the most likely } bottleneck drive in a busy filesystem. It also helps when you want to go to } management and say "hey, the system statistics claim that the drive is 95% } saturated, and the performance tuning book says you have a problem if it's } over 30%" (Solaris has a NICE performance tuning book).... } } Tools I don't have under FreeBSD but would like :-) } slowaris% iostat -x 30 } extended disk statistics } disk r/s w/s Kr/s Kw/s wait actv svc_t %w %b } fd0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 } sd0 11.8 1.2 60.0 6.5 0.0 0.3 28.2 1 29 } sd1 6.0 1.9 21.5 7.3 0.0 0.2 26.7 0 14 } sd12 44.0 15.9 313.9 102.5 1.1 4.3 90.2 3 75 } sd2 10.8 4.6 36.7 15.9 0.0 0.5 34.9 0 24 } sd3 3.0 1.5 16.4 10.5 0.1 0.1 57.9 1 10 } sd7 0.3 0.4 1.6 1.8 0.0 0.0 27.8 0 2 } } This is a fairly useful display - "wait" is the avg number of transactions } waiting for service, "actv" is the avg # of transactions actively being } serviced, svc_t is the average service time in ms, %w is the percent of time } that there are transactions waiting for service, and %b is the percent of } time the disk is busy (both derived from wait/actv). } } It clearly shows that sd12 is in some pain.... Well, that looks quite useful ... The NCR driver implements some profiling, which can be displayed using the 'ncrcontrol' utility. But it is better suited to learn about driver and drive performance, than about system performance. se@x14> ncrcontrol -vip3 T:L Vendor Device Rev Speed Max Wide Tags 0:0 Quantum XP32150 576D 10.0 10.0 8 4 4:0 HP C1533A 9406 10.0 10.0 8 - total XP32150 C1533A transf. disconn interru ---- ms/transfer ---- t/s kb/s t/s kb/s t/s kb/s length exp une fly brk total pre post disc 59 1020 60 1020 0 0 17798 97 21 60 21 10.5 0.1 0.1 1.7 74 1552 74 1552 0 0 21574 126 44 74 44 9.8 0.1 0.3 0.6 111 1021 111 1021 0 0 9416 137 22 111 22 7.1 0.2 0.2 2.4 133 190 133 190 0 0 1465 133 0 133 0 5.7 0.1 0.1 3.2 2 12 2 12 0 0 5120 0 0 2 0 1.4 0.0 0.0 0.0 total XP32150 C1533A transf. disconn interru ---- ms/transfer ---- t/s kb/s t/s kb/s t/s kb/s length exp une fly brk total pre post disc 48 812 49 812 0 0 17437 81 17 49 17 10.6 0.3 0.1 1.0 84 1492 85 1492 0 0 18257 151 42 85 42 18.6 0.2 0.1 3.1 84 1840 84 1840 0 0 22430 159 70 84 70 18.7 0.4 0.1 2.1 82 1726 82 1726 0 0 21646 149 77 82 77 20.2 0.3 0.0 3.3 86 1034 86 1034 0 0 12264 132 43 86 43 20.7 0.4 0.1 7.7 115 282 115 282 0 0 2521 130 7 115 7 17.3 0.2 0.1 11.2 130 179 130 179 0 0 1414 137 0 130 0 14.8 0.2 0.1 8.3 125 196 125 196 0 0 1606 122 0 125 0 10.3 0.1 0.0 6.3 The disk activity was one and two 'fsck -n /dev/rsd0e' (my /usr partition, some 500KB). (In the 2*fsck test, I started the second one with a two second delay, to make it access the other end of the partition and to maximize seek distances ...) } > Someone has to do the work. It would be nice if every driver didn't } > have to know how to manage the statistics. They could call (inline) } > functions but the placement of the calls is driver-dependent. } } Always the problem... somebody's gotta do the work :-) :-) Well, if we agree on some standard format, I'll make the NCR driver create the necessary data ... Regards, STefan -- Stefan Esser, Zentrum fuer Paralleles Rechnen Tel: +49 221 4706021 Universitaet zu Koeln, Weyertal 80, 50931 Koeln FAX: +49 221 4705160 ============================================================================== http://www.zpr.uni-koeln.de/~se <se@ZPR.Uni-Koeln.DE>
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