patch(es) for htop (open source process viewer for Linux)
This patch adds a
- PSS (proportional set size) field to htop.
- SWAP
- SwapPss
PSS is a newish per-process memory stat in Linux (added in version 2.6.25 of the kernel) that estimates how much memory a process really uses, after taking into account how many other processes share memory with it.
Description on wikipedia
https://en.wikipedia.org/wiki/Proportional_set_size
Article on LWN
https://lwn.net/Articles/230975/
For more info please read description of /proc/PID/smaps file.
https://www.kernel.org/doc/Documentation/filesystems/proc.txt
This problem resolved now.
There's a downside to calculating PSS in htop, and that's that it causes htop to
use a lot more CPU. This is because the Linux kernel doesn't provide PSS for
each process in a single place but instead requires scanning the entire
/proc//smaps file for each process. On my laptop with an Intel Core
i3-2350M processor, htop running with the PSS patch consumes about 20% of one
CPU. That's with an htop refresh rate (delay) of 1.5 seconds and about 60
processes running. More processes means more CPU use.
When PSS column is hidden, one cycle of LinuxProcessList_recurseProcTree took 20ms, on 181 total tasks (user/kernel threads are disabled).
When PSS column is visible, one cycle of LinuxProcessList_recurseProcTree took 200ms, on 181 total tasks, 10 times slower but not significally.
For ubuntu patched htop available here https://launchpad.net/~linvinus/+archive/ubuntu/linvinus
Other tools that show PSS
smem https://www.2daygeek.com/smem-linux-memory-usage-statistics-reporting-tool/#
libpagemap https://github.com/pholasek/libpagemap
there was a patch based on libpagemap for htop-0.9-3.fc16.src.rpm