Re: ext4 writeback performance issue in 6.12
From: Matt Fleming
Date: Thu Oct 09 2025 - 13:53:21 EST
On Thu, Oct 09, 2025 at 11:22:59AM +0100, Matt Fleming wrote:
>
> Thanks Ted. I'm going to try disabling the stripe parameter now. I'll report
> back shortly.
Initial results look very good. No blocked tasks so far and the mb
allocator latency is much improved.
mfleming@node:~$ sudo perf ftrace latency -b -a -T ext4_mb_regular_allocator -- sleep 10
# DURATION | COUNT | GRAPH |
0 - 1 us | 0 | |
1 - 2 us | 0 | |
2 - 4 us | 41 | |
4 - 8 us | 499 | ########### |
8 - 16 us | 246 | ##### |
16 - 32 us | 126 | ## |
32 - 64 us | 103 | ## |
64 - 128 us | 74 | # |
128 - 256 us | 109 | ## |
256 - 512 us | 293 | ###### |
512 - 1024 us | 448 | ########## |
1 - 2 ms | 36 | |
2 - 4 ms | 11 | |
4 - 8 ms | 1 | |
8 - 16 ms | 0 | |
16 - 32 ms | 0 | |
32 - 64 ms | 0 | |
64 - 128 ms | 0 | |
128 - 256 ms | 0 | |
256 - 512 ms | 0 | |
512 - 1024 ms | 0 | |
1 - ... s | 0 | |
Thanks,
Matt