Hi Tejun, Sorry for delayed reply, I was on vacation last week. The problem still exists in current code of 4.16.0-rc2, detail test information is below, if further info is needed please let me know. Thanks. ——————————————————————————————————————————————— Both read/write bps are limited to 10MB/s in blkio cgroup v1 & v2 $ uname -r 4.16.0-rc2+ [Without this patch]---------------------------------------- CGROUP V1 (direct write): $ dd if=/dev/zero of=/mnt/sdb1/20/test bs=1M count=1024 oflag=direct 1024+0 records in 1024+0 records out 1073741824 bytes (1.1 GB) copied, 102.402 s, 10.5 MB/s 8:16 Read 16384 8:16 Write 2684354560 8:16 Sync 2684370944 8:16 Async 0 8:16 Total 2684370944 CGROUP V1 (read): $ dd if=/mnt/sdb1/20/test of=/dev/zero bs=1M count=1024 1024+0 records in 1024+0 records out 1073741824 bytes (1.1 GB) copied, 102.412 s, 10.5 MB/s 8:16 Read 4831838208 8:16 Write 0 8:16 Sync 4831838208 8:16 Async 0 8:16 Total 4831838208 CGROUP V2 (direct write): $ cat io.max 8:16 rbps=max wbps=10485760 riops=max wiops=max $ dd if=/dev/zero of=/mnt/sdb1/20/test bs=1M count=1024 oflag=direct 1024+0 records in 1024+0 records out 1073741824 bytes (1.1 GB) copied, 102.408 s, 10.5 MB/s 8:16 rbytes=24576 wbytes=2684354560 rios=5 wios=4096 CGROUP V2 (buffered write): $ dd if=/dev/zero of=/mnt/sdb1/20/test bs=1M count=1024 1024+0 records in 1024+0 records out 1073741824 bytes (1.1 GB) copied, 0.637822 s, 1.7 GB/s 8:16 rbytes=0 wbytes=4831838208 rios=0 wios=4096 CGROUP V2 (read): $ cat io.max 8:16 rbps=10485760 wbps=max riops=max wiops=max $ dd if=/mnt/sdb1/20/test of=/dev/zero bs=1M count=1024 1024+0 records in 1024+0 records out 1073741824 bytes (1.1 GB) copied, 102.409 s, 10.5 MB/s 8:16 rbytes=4831846400 wbytes=0 rios=4097 wios=0 [With this patch]---------------------------------------- CGROUP V1 (direct write): $ dd if=/dev/zero of=/mnt/sdb1/20/test bs=1M count=1024 oflag=direct 1024+0 records in 1024+0 records out 1073741824 bytes (1.1 GB) copied, 102.402 s, 10.5 MB/s 8:16 Read 24576 8:16 Write 1073741824 8:16 Sync 1073766400 8:16 Async 0 8:16 Total 1073766400 CGROUP V1 (read): $ dd if=/mnt/sdb1/20/test of=/dev/zero bs=1M count=1024 1024+0 records in 1024+0 records out 1073741824 bytes (1.1 GB) copied, 102.406 s, 10.5 MB/s 8:16 Read 1073741824 8:16 Write 0 8:16 Sync 1073741824 8:16 Async 0 8:16 Total 1073741824 CGROUP V2 (direct write): $ dd if=/dev/zero of=/mnt/sdb1/20/test bs=1M count=1024 oflag=direct 1024+0 records in 1024+0 records out 1073741824 bytes (1.1 GB) copied, 102.407 s, 10.5 MB/s 8:16 rbytes=16384 wbytes=1073741824 rios=4 wios=1024 CGROUP V2 (buffered write): $ dd if=/dev/zero of=/mnt/sdb1/20/test bs=1M count=1024 1024+0 records in 1024+0 records out 1073741824 bytes (1.1 GB) copied, 0.650783 s, 1.6 GB/s 8:16 rbytes=0 wbytes=1073741824 rios=0 wios=512 CGROUP V2 (read): $ dd if=/mnt/sdb1/20/test of=/dev/zero bs=1M count=1024 1024+0 records in 1024+0 records out 1073741824 bytes (1.1 GB) copied, 102.411 s, 10.5 MB/s 8:16 rbytes=1077314048 wbytes=0 rios=572 wios=0 ——————————————————————————————————————————————— > 在 2018年2月13日，下午10:43，Tejun Heo <tj@xxxxxxxxxx> 写道： > > On Tue, Feb 13, 2018 at 02:45:50PM +0800, Chengguang Xu wrote: >> In current throttling/upper limit policy of blkio cgroup >> blkio.throttle.io_service_bytes does not exactly represent >> the number of bytes issued to the disk by the group, sometimes >> this number could be counted multiple times of real bytes. >> This fix introduces BIO_COUNTED flag to avoid multiple counting >> for same bio. >> >> Signed-off-by: Chengguang Xu <cgxu519@xxxxxxxxxx> > > We had a series of fixes / changes for this problem during the last > cycle. Can you please see whether the current linus master has the > same problem. > > Thanks. > > -- > tejun
