On Tue, 6 Apr 2004, Xin LI wrote: > On Tue, Apr 06, 2004 at 11:03:13AM +0400, Artem Koutchine wrote: > > While booting i see many drivers marked > > as [Giant-locked]. > > Is being Giant-locked good or bad what are the > > implications? > It's not good if you have a computer with multiple processors. I have a box with 4 ppro-200 cpus. It has 4 adaptec eisa scsi controllers, each controlling 2 disks. All 8 disks are in the same vinum raid-5 volume. I have a large (1.5gig) file on this volume. This is what happens when I run md5 on this file 4 times concurrently: %%% > md5 really-big-file & [2] 78243 > md5 really-big-file & [3] 78244 > md5 really-big-file & [4] 78245 > md5 really-big-file & [5] 78246 > vmstat -c10 -w6 procs memory page disks faults cpu r b w avm fre flt re pi po fr sr ad0 am0 in sy cs us sy id 1 2 3 73308 28668 235 1 1 0 255 16 0 0 362 390 829 8 4 88 1 2 3 73308 21300 0 0 0 0 310 0 0 0 382 5928 11671 8 28 64 1 1 3 73308 29248 0 0 0 0 323 653 0 0 384 5769 11363 8 27 65 2 2 2 73308 20592 31 0 1 0 393 0 2 0 423 5614 11226 8 28 64 2 2 2 73308 27968 0 0 0 0 347 653 1 0 420 5655 11352 7 29 64 2 3 2 73308 19940 0 0 0 0 335 0 0 0 385 5563 11108 7 28 65 2 3 2 73308 26788 0 0 0 0 369 654 0 0 391 5608 11168 8 27 65 2 2 2 73308 34112 0 0 0 0 354 653 0 0 391 5656 11352 8 28 64 2 3 2 73308 25064 0 0 0 0 375 0 0 0 393 5687 11315 8 27 65 2 3 2 73308 32512 0 0 0 0 344 655 0 0 386 5664 11284 8 27 65 %%% As you can see, only 8% of all cpus are being used to calculate the md5s. At least 2 cpus are constantly idle. > grep GIANT /var/run/dmesg.boot fxp0: [GIANT-LOCKED] ahc0: [GIANT-LOCKED] ahc1: [GIANT-LOCKED] ahc2: [GIANT-LOCKED] ahc3: [GIANT-LOCKED] amr0: [GIANT-LOCKED] ahc4: [GIANT-LOCKED] ahc5: [GIANT-LOCKED] atkbd0: [GIANT-LOCKED] -- :{ andyf_at_speednet.com.au Andy Farkas System Administrator Speednet Communications http://www.speednet.com.au/Received on Mon Apr 05 2004 - 22:57:32 UTC
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