Messages in this thread |  | | Date | Mon, 18 Mar 2002 12:14:27 -0800 | From | Andrew Morton <> | Subject | Re: [CFT] delayed allocation and multipage I/O patches for 2.5.6. |
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Hanna Linder wrote: > > --On Monday, March 11, 2002 22:00:57 -0800 Andrew Morton <akpm@zip.com.au> wrote: > > > "help, help - there's no point in just one guy testing this" (thanks Randy). > > Will you accept the testing of a gal? ;)
With alacrity :) Thanks.
> > > > This is an update of the delayed-allocation and multipage pagecache I/O > > patches. I'm calling this a beta, because it all works, and I have > > other stuff to do for a while. > > > > Here are the dbench throughput results on an 8-way SMP with 2GB memory. > These are run with 64 then 128 clients 15 times each averaged. It looked > pretty good. > Running with more than 180 clients caused the system to hang, after > a reset there was much filesystem corruption. This happened twice. Probably > related to filling up disk space.
It could be space-related. A couple of gigs should have been plenty..
One other possible explanation is to do with radix-tree pagecache. It has to allocate memory to add nodes to the tree. When these allocations start failing due to out-of-memory, the VM will keep on calling swap_out() a trillion times without noticing that it didn't work out. But if this happened, yo would have seen a huge number of "0-order allocation failed" messages.
> There are no ServerRaid drivers for 2.5 yet > so the biggest disks on this system are unusable. lockmeter results are forthcoming (day or two). > > Running dbench on an 8-way SMP 15 times each. > > 2.5.6 clean > > Clients Avg > > 64 37.9821 > 128 29.8258 > > 2.5.6 with everything.patch > > Clients Avg > > 64 41.0204 > 128 30.6431 >
That's odd. I'm showing 50% increases in dbench throughput. Not that there's anything particularly clever about that - these patches allow the kernel to just throw more memory in dbench's direction, and it likes that. But it does indicate that something funny is up. I'll take a closer look - thanks again.
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