weiser.pa@xerox.com (06/11/88)
aglew@urbsdc.urbana.gould.com says: "I don't have Sun 4 source at hand right now, but if their scheduler is similar to the standard BSD scheduler a process coming out of a sleep may [*] have its priority boosted. ...[further explanation here...]" But this explanation doesn't explain why Sun's show this behavior and Vaxes don't, nor why Sun-3's, with 8 MMU contexts, show the knee at 8 fast sleepers, and Sun-4 with 16 MMU contexts show it at 16! -mark
mash@mips.COM (John Mashey) (06/11/88)
In article <16138@brl-adm.ARPA> weiser.pa@xerox.com writes: >aglew@urbsdc.urbana.gould.com says: >"I don't have Sun 4 source at hand right now, but if their scheduler >is similar to the standard BSD scheduler a process coming out of >a sleep may [*] have its priority boosted. ...[further explanation here...]" > >But this explanation doesn't explain why Sun's show this behavior and Vaxes >don't, nor why Sun-3's, with 8 MMU contexts, show the knee at 8 fast sleepers, >and Sun-4 with 16 MMU contexts show it at 16! A VAX uses a TLB, whose user portion must be flushed upon each context switch, i.e., in some sense, it has 1 context (although this is not strictly the same kind of context, as it does not need to be mass saved/restored). Hence, there is no reason for a VAX to have a MMU-related knee anywhere. -- -john mashey DISCLAIMER: <generic disclaimer, I speak for me only, etc> UUCP: {ames,decwrl,prls,pyramid}!mips!mash OR mash@mips.com DDD: 408-991-0253 or 408-720-1700, x253 USPS: MIPS Computer Systems, 930 E. Arques, Sunnyvale, CA 94086
friedl@vsi.UUCP (Stephen J. Friedl) (06/12/88)
In article <2356@winchester.mips.COM>, mash@mips.COM (John Mashey) writes:
< [performance knees on Sun & friends]
<
< A VAX uses a TLB, whose user portion must be flushed upon each context
< switch, i.e., in some sense, it has 1 context (although this is not
< strictly the same kind of context, as it does not need to be mass
< saved/restored). Hence, there is no reason for a VAX to have a
< MMU-related knee anywhere.
Alternatively, it has a (smaller) knee at 1, 2, 3, .... :-)
--
Steve Friedl V-Systems, Inc. (714) 545-6442 3B2-kind-of-guy
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Nancy Reagan on ptr args with a prototype in scope: "Just say NULL"