62 lines
2.2 KiB
Diff
62 lines
2.2 KiB
Diff
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From 6e43ce523e7b403cc4f5e94c988d8811d2053e0f Mon Sep 17 00:00:00 2001
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From: John Kacur <jkacur@redhat.com>
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Date: Tue, 14 Dec 2021 14:59:50 -0500
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Subject: [PATCH] tuna: Fix tuna displays incorrect cpu affinity when cpu is
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offlined
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If we create a process and query it's affinity, both taskset and tuna
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display the same result, but if we then disable a processor, tuna
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displays the wrong affinity, as below.
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[jkacur@fionn tuna]$ sha1sum /dev/zero &
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[1] 10640
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[jkacur@fionn tuna]$ taskset -p 10640
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pid 10640's current affinity mask: fff
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[jkacur@fionn tuna]$ su -c './tuna-cmd.py -t sha1sum -P'
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Password:
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thread ctxt_switches
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pid SCHED_ rtpri affinity voluntary nonvoluntary cmd
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10640 OTHER 0 0xfff 0 423 sha1sum
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[jkacur@fionn tuna]$ su -c 'chcpu -d 5'
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Password:
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CPU 5 disabled
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[jkacur@fionn tuna]$ taskset -p 10640
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pid 10640's current affinity mask: fdf
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[jkacur@fionn tuna]$ su -c './tuna-cmd.py -t sha1sum -P'
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Password:
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thread ctxt_switches
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pid SCHED_ rtpri affinity voluntary nonvoluntary cmd
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10640 OTHER 0 0x7df 0 919 sha1sum
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The reason for this is that after tuna gets the affinity for the
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process, when it converts this to a hex value, it passes the number of
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enabled processors to hexbitmask in procfs, when what we really need is
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the number of processors including disabled ones.
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Fix this by querrying SC_NPROCESSORS_CONF and passing that value to
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hexbitmask.
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Signed-off-by: John Kacur <jkacur@redhat.com>
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---
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tuna-cmd.py | 4 +++-
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1 file changed, 3 insertions(+), 1 deletion(-)
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diff --git a/tuna-cmd.py b/tuna-cmd.py
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index d209a2e89493..7e33a128d676 100755
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--- a/tuna-cmd.py
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+++ b/tuna-cmd.py
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@@ -199,7 +199,9 @@ def format_affinity(affinity):
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if len(affinity) <= 4:
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return ",".join(str(a) for a in affinity)
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- return ",".join(str(hex(a)) for a in procfs.hexbitmask(affinity, get_nr_cpus()))
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+ # We need the number of cpus on a system, including disabled ones
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+ ncpus = os.sysconf('SC_NPROCESSORS_CONF')
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+ return ",".join(str(hex(a)) for a in procfs.hexbitmask(affinity, ncpus))
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def ps_show_thread(pid, affect_children, ps, has_ctxt_switch_info, sock_inodes,
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--
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2.31.1
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