On Thu, Feb 27, 2025 at 5:20 PM Sapkal, Swapnil <swapnil.sapkal@xxxxxxx> wrote: > I tried reproducing the issue with both the scenarios mentioned below. > > > 1. with 1 fd instead of 20: > > > > /usr/bin/hackbench -g 16 -f 1 --threads --pipe -l 100000 -s 100 > > > > With this I was not able to reproduce the issue. I tried almost 5000 > iterations. > Ok, noted. > > 2. with a size which divides 4096 evenly (e.g., 128): > > > > /usr/bin/hackbench -g 1 -f 20 --threads --pipe -l 100000 -s 128 > > I was not able to reproduce the issue with 1 group. But I thought you > wanted to change only the message size to 128 bytes. Yes indeed, thanks for catching the problem. > When I retain the number of groups to 16 and change the message size to > 128, it took me around 150 iterations to reproduce this issue (with 100 > bytes it was 20 iterations). The exact command was > > /usr/bin/hackbench -g 16 -f 20 --threads --pipe -l 100000 -s 128 > > I will try to sprinkle some trace_printk's in the code where the state > of the pipe changes. I will report here if I find something. > Thanks. So to be clear, this is Oleg's bug, I am only looking from the side out of curiosity what's up. As it usually goes with these, after the dust settles I very much expect the fix will be roughly a one liner. :) -- Mateusz Guzik <mjguzik gmail.com>
