On Tue 07-01-20 11:57:08, Theodore Y. Ts'o wrote:
On Tue, Jan 07, 2020 at 02:41:06PM +0100, Jan Kara wrote:Are you sure? I can see:
Hello,A "-20.2% regression" should be read as a "20.2% performance
On Tue 24-12-19 08:59:15, kernel test robot wrote:
FYI, we noticed a -20.2% regression of filebench.sum_bytes_mb/s due to commit:I was trying to reproduce this but I failed with my test VM. I had SATA SSD
commit: b1b4705d54abedfd69dcdf42779c521aa1e0fbd3 ("ext4: introduce direct I/O read using iomap infrastructure")
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master
in testcase: filebench
on test machine: 8 threads Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz with 8G memory
with following parameters:
disk: 1HDD
fs: ext4
test: fivestreamreaddirect.f
cpufreq_governor: performance
ucode: 0x27
as a backing store though so maybe that's what makes a difference. Maybe
the new code results in somewhat more seeks because the five threads which
compete in submitting sequential IO end up being more interleaved?
improvement" is zero-day kernel speak.
58.30 Â 2% -20.2% 46.53 filebench.sum_bytes_mb/s
which implies to me previously the throughput was 58 MB/s and after the
commit it was 46 MB/s?
Anyway, in my testing that commit made no difference in that benchmark
whasoever (getting around 97 MB/s for each thread before and after the
commit).
Honza