Messages in this thread | | | Date | Tue, 9 Jan 2001 20:54:20 +0100 | From | Andrea Arcangeli <> | Subject | Re: [PLEASE-TESTME] Zerocopy networking patch, 2.4.0-1 |
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On Tue, Jan 09, 2001 at 07:38:28PM +0100, Ingo Molnar wrote: > > On Tue, 9 Jan 2001, Jens Axboe wrote: > > > > > ever seen, this is why i quoted it - the talk was about block-IO > > > > performance, and Stephen said that our block IO sucks. It used to suck, > > > > but in 2.4, with the right patch from Jens, it doesnt suck anymore. ) > > > > > > Thats fine. Get me 128K-512K chunks nicely streaming into my raid controller > > > and I'll be a happy man > > > > No problem, apply blk-13B and you'll get 512K chunks for SCSI and RAID. > > i cannot agree more - Jens' patch did wonders to IO performance here. It
BTW, I noticed what is left in blk-13B seems to be my work (Jens's fixes for merging when the I/O queue is full are just been integrated in test1x). The 512K SCSI command, wake_up_nr, elevator fixes and cleanups and removal of the bogus 64 max_segment limit in scsi.c that matters only with the IOMMU to allow devices with sg_tablesize <64 to do SG with 64 segments were all thought and implemented by me. My last public patch with most of the blk-13B stuff in it was here:
ftp://ftp.us.kernel.org/pub/linux/kernel/people/andrea/patches/2.4.0-test7/blkdev-3
I sumbitted a later revision of the above blkdev-3 to Jens and he kept nicely maintaining it in sync with 2.4.x-latest.
My blkdev tree is even more advanced but I didn't had time to update with 2.4.0 and marge it with Jens yet (I just described to Jens what "more advanced" means though, in practice it means something like a x2 speedup in tiotest seek write numbers, streaming I/O doesn't change on highmem boxes but it doesn't hurt lowmem boxes anymore). Current blk-13B isn't ok for integration yet because it hurts with lowmem (try with mem=32m with your scsi array that gets 512K*512 requests in flight :) and it's not able to exploit the elevator as well as my tree even on highmemory machines. So I'd wait until I merge the last bits with Jens (I raised the QUEUE_NR_REQUESTS to 3000) before inclusion.
Confirm Jens?
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