Date: Thu, 05 Jun 2025 00:13:30 +0200 From: Olivier Certner <olce@freebsd.org> To: freebsd-hackers@freebsd.org, freebsd-arch@freebsd.org Subject: Soon committing the "256-queue runqueue" scheduler work Message-ID: <2038652.ruP0FAUDoQ@ravel>
index | next in thread | raw e-mail
[-- Attachment #1 --] Hello, I'm planning to commit into main/-CURRENT (with a one-month MFC) the "256-queue runqueue" scheduler work and related commits (see the series of reviews starting at https://reviews.freebsd.org/D45387). The user-visible effects of it should be: - The 32 realtime priority levels, and the 32 idle priority ones, are now going to be really distinct. Previously, levels with the same quotient when divided by 4 were aliased (separately in each class). - Priority numbers (under PRI in top(1) and ps(1)) will change (conveniently, 0 will now be the first (=highest priority) timesharing level; negative values thus indicate any high priority thread that can preempt timesharing or idle-priority ones). - Accuracy of reported %CPU per-thread will improve slightly (when using ^T, ps(1) or systat(1), or in applications using field 'ki_pctcpu' of 'struct kinfo_proc'). - Perhaps tiny latency improvements (in average and stddev), although these may not be considered statistically significant. All other scheduler characteristics should be practically unchanged. The code changes have been mostly done almost a year ago, and have been tested since then on various machines and workloads, and also with specific tests for ensuring that fairness, anti-starvation and nice values behaviors have not been changes. Please see in particular D46566 for more details. If some are interested to have a look at this work and have not seized the opportunity yet, now would be a good time to do so. Thanks and regards. -- Olivier Certner [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- iQIzBAABCQAdFiEEmNCxHjkosai0LYIujKEwQJceJicFAmhAxQoACgkQjKEwQJce JidOaw//ZkRVKDMO4crJIRn0YCH3AZwmkU0dtfdjD+4mVNq84lFTYMPTp2DFNUZn oHtGGn87cVSJ4KY9uI69xMPqFdyd0AgsqTpjD563MsHqYq2Qc465NoynGBbMM+sx 8r1DHUJckhTpkQALn13eug2/AJzt3Z2Tp3BSEsyCEVyDRlf1nrItj8bLnAwFtq21 9Xen6qI9UBhl55/HNPj/Gem/FVLbS/3UmSCV09WPVu9XtAA6pNI4xEp4DfQ5ZeoU 5Q3oT+6SB2Cxc7iUVnlUFu91dkmt2URXB0QbSPzFDDTSGKyiHIPBjgLegcI6mbGY ZEUBfPa69kZUdBc3STcW56t05VwPE9JW4aVtHqQI+yotANx5A7D1ChWR75N3jhCg xKikmaaCo04L6bHHn12hZPjuJTGpBoLNwBmBDnsAjSeuJRev0LswzG0Lu6YJRkJn LuqIr1aAfvkIgd7JXzrkuQ8TIEqHGUySThOM84zqib4Cgh4RmaZjpayZ0KLO1+5k Qd0+yI/+BA5AGjTEkR6tHeCPJsnhxkyDAQ2wl9OyohSl3PcdGcUrmuDTdJ/PsCGS 4X8/7eIfvgWGzXFmYrMZvJ+/TH7Lh8NPEB3e5HSZdMUV/3Llfwv+jXG+FdZy6xnQ o3MLaiXHZ9dawmoeUIKqthCOOMAqDZr9UhncA0u+yr5B+SjdbV0= =h5LH -----END PGP SIGNATURE-----help
Want to link to this message? Use this
URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?2038652.ruP0FAUDoQ>