b89261ba01
Due to differences in (mainly) measuring and accumulating CPU times, the two top programs end up serving different purposes: the NetBSD top is a system administration tool, while the MINIX3 top (now mtop) is a performance debugging tool. Therefore, we keep both. The newly imported BSD top has a few MINIX3-specific changes. CPU statistics separate system time from kernel time, rather than kernel time from time spent on handling interrupts. Memory statistics show numbers that are currently relevant for MINIX3. Swap statistics are disabled entirely. All of these changes effectively bring it closer to how mtop already worked as well. Change-Id: I9611917cb03e164ddf012c5def6da0e7fede826d
31 lines
1.4 KiB
Groff
31 lines
1.4 KiB
Groff
.SH "LINUX NOTES"
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The Linux port was written by Richard Henderson <rth@tamu.edu>.
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The CPU% calculation was brazenly stolen from the Solaris 2
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port and should be attributed to one of the many names listed
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in its man page.
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The order support was stolen from the SunOS 5 port by
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Alexey Klimkin <kad@klon.tme.mcst.ru>
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Made to work under 2.4 by William LeFebvre.
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This version of the Linux port includes automatic thread "eliding".
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In Linux, a thread is treated as another process sharing the memory
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space (as well as file table and other resources). Thus
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multiple threads appear as separate processes in most system
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utilities (see
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.IR clone (2)).
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This version of top detects child thread processes and does not
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display them separately. Instead of displaying threads individually,
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an extra column "THR" shows the number of thread processes for a
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parent process. The cpu time and percentages are added to the
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parent. This gives a display much closer to other thread-capable Unix
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systems. However, threads are still counted as separate processes in
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the process summary line.
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A process is considered a thread of its parent if the
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following values are identical to its parent: address space size,
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resident set size, code start and end program counters, and stack
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start. This heuristic can mistake a recently forked child as a thread,
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until the child has either called exec or allocated space on its own.
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