On Thu, 15 May 2008, Matthew Wilcox wrote: > Or possibly your assumptions have been the main factor. I gave you a > reproducer for this problem 6 weeks ago. As far as I can tell, you > haven't run it since. Assumptions may be the issue. My own "reproducer" for remote frees is available from my git tree and I usually prefer to run my own. We discussed the results of that program last fall. You stated yesterday that your code is proprietary. I am not sure what I am allowed to do with the code. I did not know that it was proprietary before yesterday and I would have just forwarded that code to Pekka yesterday if I would not have caught that message in time. I thought that what you provided it was a test program to exercise and optimize the scsi subsystem? > > > > You could just start with 2.6.25.X which already contains the slab > > > > statistics. > > > > > > Certainly. Exactly how does collecting these stats work? Am I supposed > > > to zero the counters after the TPC has done its initial ramp-up? What > > > commands should I run, and at exactly which points? > > > > Compile slabinfo and then do f.e. slabinfo -AD (this is documented in the > > help text provided when enabling statistics). > > That's an utterly unhelpful answer. Let me try asking again. > > Exactly how does collecting these stats work? Am I supposed to zero > the counters after the TPC has done its initial ramp-up? What commands > should I run, and at exactly which points? There is no way of zeroing the counters. Run slabinfo -AD after the test application has been running for awhile. If you want a differential then you have to take two datapoints. > Otherwise I'll get something wrong and these numbers will be useless to > you. Or that's what you'll claim anyway. No. I guess I will end up with a lot of guess work of what is going on on the system since the information is limited for some reason. > For reference the helptext says: > > SLUB statistics are useful to debug SLUBs allocation behavior in > order find ways to optimize the allocator. This should never be > enabled for production use since keeping statistics slows down > the allocator by a few percentage points. The slabinfo command > supports the determination of the most active slabs to figure > out which slabs are relevant to a particular load. > Try running: slabinfo -DA > > By the way, when you say 'compile slabinfo', you mean the file shipped > as Documentation/vm/slabinfo.c (rather than, say, something out of tree?) Yes. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
