Hi Sitsofe, Sorry if this email troubled you but I could not find any useful information for this. I am getting the question with fio page cache bypass option (direct=1 ioengine=libaio) I am using fio version 2.19 with command: fio --filename=/opt/test --direct=1 --rw=randrw --randrepeat=0 --ioengine=libaio --bs=4k --rwmixread=75 --iodepth=16 --numjobs=1 --name=4ktest --size=1G and i used cachestat tool from here to monitor: https://github.com/brendangregg/perf-tools The output was: Counting cache functions... Output every 1 seconds. HITS MISSES DIRTIES RATIO BUFFERS_MB CACHE_MB 1399 42 0 97.1% 2 31 1408 0 0 100.0% 2 31 -68699 39 71478 100.1% 3 532 -21325 0 22886 100.0% 3 621 -19956 0 21492 100.0% 3 705 -13739 0 15254 100.0% 3 765 As far as i know the buffer cache and page cache was unified from Linux kernel version 2.4. So i wondered why fio with option direct=1 that didn’t bypass page cache as it should? I didn’t see page cache increasing when using dd with oflag=direct to copy or write file to disk. Please correct me if i am wrong. Thanks a lot in advance. Regards, Son -- To unsubscribe from this list: send the line "unsubscribe fio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
