On Sun, 26 Nov 2023 22:44:45 -0800 Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote: > Hi Shushu, > > the work certainly l-ooks interesting! > > However: > > > Optimized by using fine-grained locks, customized data structures, > > and scattered address space. Achieves significant improvements in > > both throughput and latency. > > this is a lot of work for a single Linux patch, we usually do that > work pice by pice instead of complete rewrite, and for such > signigicant changes the commit logs also tend to be a bit extensive. > > I'm also not quite sure what scattered address spaces are - I bet > reading the paper (I plan to get to that) would explain it, but it > also helps to explain the idea in the commit message. > > That's my high level nitpicking for now, I'll try to read the paper > and the patch in detail and come back later. > > Hi Everyone, I went ahead and ran a series of performance tests on this patch to help the community understand the value.Here's a summary of what have completed and am happy to run some more to keep the patch moving. I have not yet reviewed the code as I wanted to make sure it provided good benefit first and it does for sure. I will be reviewing shortly. Here is a summary of my tests: * Kioxia CM7 drives https://americas.kioxia.com/content/dam/kioxia/shared/business/ssd/enterprise-ssd/asset/productbrief/eSSD-CM7-V-product-brief.pdf * Dual Socket Xeon 8368 2.4GHz 256G RAM * Results are the average of just 2 60 second runs per data point, if interest continues I can re-run to eliminate any potential anomalies * I used 8 fio jobs per disk and 2 group_thread_cnt per disk so when reading the graph, for example, 8DR5_patch_64j15gtc means an 8 Disk RAID5 run against the patch with 64 fio jobs and group-thread_cnt set to 16. 'base' in the name is md-next branch as of yesterday. * Sample fio command: fio --filename=/dev/md0 --direct=1 --output=/root/remote/8DR5_patch_64j16gtc_1/randrw_131072_1.json --rw=randrw --bs=131072 --ioengine=libaio --ramp_time=3 --runtime=60 --iodepth=1 --numjobs=64 --time_based --group_reporting --name=131072_1_randrw --output-format=json --numa_cpu_nodes=0 Results: https://photos.app.goo.gl/Cip1rU3spbD8nvG28 -Paul
