sched: Use a relative alarm
authorBarret Rhoden <brho@cs.berkeley.edu>
Mon, 14 Aug 2017 13:42:52 +0000 (09:42 -0400)
committerBarret Rhoden <brho@cs.berkeley.edu>
Mon, 14 Aug 2017 21:02:20 +0000 (17:02 -0400)
commita6940a9e28bffeddf810af64c01026071244631b
treed8f892a1aacaa2c5b8635b11ad6f4e48d9d63da2
parent9e00dd8de6088062372fae2ed6c0cd3aa3f20c5a
sched: Use a relative alarm

Some syscalls, notably writing to the serial console, take a very long
time.  If you cat a large file to the console, your other SCPs (notably
SSH and shells) get nearly no service.  The ksched backlogs about a
dozen ksched_ticks during the syscalls, which are O(100ms).  With this
change, those other processes get a little more attention.

Signed-off-by: Barret Rhoden <brho@cs.berkeley.edu>
kern/src/schedule.c