Hannover Messe 2024
COOL - Compact OSADL Online Lectures - April 2024 edition
HOT - Heidelberg OSADL Talks 2024 (online event)
OSADL Networking Day 2024 in Heidelberg, Germany
Scripts to set the SMP affinity mask of kernel threads
IRQ threads - Non-IRQ kernel threads
#!/bin/bash defaultmask=7 cpucores=`grep ^processor /proc/cpuinfo | wc -l` if test $cpucores -gt 16 then coremask=4294967295 elif test $cpucores -gt 8 then coremask=65535 elif test $cpucores -gt 4 then coremask=255 else coremask=15 fi eval `cat /proc/cmdline | tr ' ' '\n' | grep isolcpus` if test "$isolcpus" then OLDIFS="$IFS" IFS=, isolmask=0 for i in $isolcpus do thismask=$((2 ** $i)) isolmask=$(($isolmask + $thismask)) done IFS="$OLDIFS" fi if test "$isolmask" then decidefaultmask=$(($coremask ^ $isolmask)) defaultmask=`printf %x $decidefaultmask` fi if test "$1" -a "$1" = --help then echo "Usage: `basename $0` <mask>" echo "Function: Set SMP affinity mask of kernel threads to <mask>" echo " <mask> defaults to $defaultmask" echo "Options: none" exit 1 fi if test "$1" then if echo $1 | grep -iq [^0-9a-f] then echo "Argument is expected to be a lower-case hexadecimal number, not $1" exit 1 fi mask=$1 else mask=$defaultmask fi mask10=`printf %d 0x$mask` redcolor='\033[0;31m' yellowcolor='\033[0;33m' greencolor='\033[0;32m' nocolor='\033[0m' red() { printf $redcolor$@$nocolor } yellow() { printf $yellowcolor$@$nocolor } green() { printf $greencolor$@$nocolor } NOT() { echo `red NOT` } is() { echo `green is` } can() { echo `yellow can` } could() { echo `yellow could` } cd /proc for i in `ls -1d [0-9]* | sort -n` do if grep -q "PPid:\W2$" $i/status 2>/dev/null then if grep -q -e "/[0-9]*$" -e "/[0-9]:" -e "^irq/[0-9]" $i/comm 2>/dev/null then # echo Affinity mask of kernel IRQ thread `cat $i/comm` will not be modified continue fi realcore10=`ps -o psr $i | sed 's/^ *//' | grep ^[0-9]` realcoremask10=$((2 ** $realcore10)) affinity=`grep Cpus_allowed: $i/status | cut -f2 | sed s/^0*//` flags=`cat $i/stat | sed 's/(.*)/comm/' | cut -d" " -f 9` if test $(($flags & 0x04000000)) != 0 then echo -n Affinity of `cat $i/comm` "($i)" can `NOT` be modified, since it has the PF_NO_SETAFFINITY flag set if test $((0x$affinity - 0x$mask)) = 0 then if test $(($realcoremask10 & 0x$mask)) != 0 then echo ", but the affinity mask 0x$affinity fortunately `is` correct, and the thread is currently running on core $realcore10 which `is` ok" else echo ", but the affinity mask 0x$affinity fortunately `is` correct; however, the thread is currently running on core $realcore10 which is `NOT` ok" fi else if test $(($realcoremask10 & 0x$mask)) != 0 then echo ", but although the affinity mask is 0x$affinity which is `NOT` ok, the thread is currently running on core $realcore10 which `is` ok" else echo ", and because the affinity mask unfortunately is 0x$affinity which is `NOT` ok, the thread is running on core $realcore10 which is `NOT` ok" fi fi continue fi if test $((0x$affinity - 0x$mask)) = 0 then echo -n Affinity of `cat $i/comm` "($i)" already is 0x$mask which `is` ok if test $(($realcoremask10 & 0x$mask)) != 0 then echo ", and the thread is currently running on core $realcore10 which `is` ok" else echo ", but the thread is currently running on core $realcore10 which is `NOT` ok" fi continue fi if taskset -p $mask $i >/dev/null 2>&1 then echo -n Affinity of `cat $i/comm` "($i)" was successfully attempted to be modified to 0x$mask realcore10=`ps -o psr $i | sed 's/^ *//' | grep ^[0-9]` realcoremask10=$((2 ** $realcore10)) affinity=`grep Cpus_allowed: $i/status | cut -f2 | sed s/^0*//` if test $((0x$affinity - 0x$mask)) = 0 then if test $(($realcoremask10 & 0x$mask)) != 0 then echo " and `is` now 0x$mask, and the thread is currently running on core $realcore10 which `is` ok" else echo " and `is` now 0x$mask, but the thread is currently running on core $realcore10 which is `NOT` ok" fi else echo -n , but still is $affinity which `is` if test $((0x$affinity & 0x$mask)) != 0 then if test $(($realcoremask10 & 0x$mask)) != 0 then echo ok, and the thread is currently running on core $realcore10 which also `is` ok else echo numerically ok, but the thread is currently running on core $realcore10 which is `NOT` ok fi else if test $(($realcoremask10 & 0x$mask)) != 0 then echo `NOT` ok, but the thread is currently running on core $realcore10 which `is` ok else echo `NOT` ok, and the thread is in fact currently running on core $realcore10 which is `NOT` ok fi fi fi else echo -n Affinity of `cat $i/comm` "($i)" could not be modified to 0x$mask masklen=`echo -n $mask | wc -c` affinitylen=`echo -n $affinity | wc -c` if test $affinitylen -gt $masklen then start=`expr $affinitylen - $masklen + 1` testaffinity=`echo $affinity | cut -c$start-$affinitylen` else testaffinity=$affinity fi if test $((~0x$mask & 0x$testaffinity)) = 0 then if test $(($realcoremask10 & 0x$mask)) != 0 then echo , but is 0x$affinity and `is` ok, and the thread is currently running on core $realcore10 which `is` ok else echo , but is 0x$affinity and `could` be ok, but the thread is currently running on core $realcore10 which is `NOT` ok fi else if test $(($realcoremask10 & 0x$mask)) != 0 then echo " and still is 0x$affinity which is `NOT` ok, but the thread is currently running on core $realcore10 which `is` ok" else echo " and still is 0x$affinity which is `NOT` ok, and the thread is in fact currently running on core $realcore10 which is `NOT` ok" fi fi fi fi done
Output of the above script when running it on the 4-core system at rack #5, slot #4 at shadow position
Affinity of rcu_gp (3) can NOT be modified, since it has the PF_NO_SETAFFINITY flag set, but although the affinity mask is 0xff which is NOT ok, the thread is currently running on core 0 which is ok Affinity of rcu_par_gp (4) can NOT be modified, since it has the PF_NO_SETAFFINITY flag set, but although the affinity mask is 0xff which is NOT ok, the thread is currently running on core 0 which is ok Affinity of mm_percpu_wq (8) can NOT be modified, since it has the PF_NO_SETAFFINITY flag set, but although the affinity mask is 0xff which is NOT ok, the thread is currently running on core 0 which is ok Affinity of rcu_preempt (11) already is 0x7 which is ok, and the thread is currently running on core 2 which is ok Affinity of kdevtmpfs (40) already is 0x7 which is ok, but the thread is currently running on core 3 which is NOT ok Affinity of netns (41) can NOT be modified, since it has the PF_NO_SETAFFINITY flag set, but although the affinity mask is 0xff which is NOT ok, the thread is currently running on core 0 which is ok Affinity of rcu_tasks_kthre (42) already is 0x7 which is ok, and the thread is currently running on core 1 which is ok Affinity of kauditd (43) already is 0x7 which is ok, and the thread is currently running on core 2 which is ok Affinity of khungtaskd (45) already is 0x7 which is ok, and the thread is currently running on core 1 which is ok Affinity of oom_reaper (46) already is 0x7 which is ok, and the thread is currently running on core 2 which is ok Affinity of writeback (47) can NOT be modified, since it has the PF_NO_SETAFFINITY flag set, but although the affinity mask is 0xff which is NOT ok, the thread is currently running on core 2 which is ok Affinity of kcompactd0 (48) already is 0x7 which is ok, and the thread is currently running on core 2 which is ok Affinity of ksmd (49) already is 0x7 which is ok, and the thread is currently running on core 1 which is ok Affinity of cryptd (69) can NOT be modified, since it has the PF_NO_SETAFFINITY flag set, but although the affinity mask is 0xff which is NOT ok, the thread is currently running on core 1 which is ok Affinity of kintegrityd (104) can NOT be modified, since it has the PF_NO_SETAFFINITY flag set, but although the affinity mask is 0xff which is NOT ok, the thread is currently running on core 2 which is ok Affinity of kblockd (105) can NOT be modified, since it has the PF_NO_SETAFFINITY flag set, but although the affinity mask is 0xff which is NOT ok, the thread is currently running on core 0 which is ok Affinity of blkcg_punt_bio (106) can NOT be modified, since it has the PF_NO_SETAFFINITY flag set, but although the affinity mask is 0xff which is NOT ok, the thread is currently running on core 1 which is ok Affinity of ata_sff (108) can NOT be modified, since it has the PF_NO_SETAFFINITY flag set, but although the affinity mask is 0xff which is NOT ok, the thread is currently running on core 2 which is ok Affinity of md (109) can NOT be modified, since it has the PF_NO_SETAFFINITY flag set, but although the affinity mask is 0xff which is NOT ok, the thread is currently running on core 0 which is ok Affinity of edac-poller (110) can NOT be modified, since it has the PF_NO_SETAFFINITY flag set, but although the affinity mask is 0xff which is NOT ok, the thread is currently running on core 1 which is ok Affinity of devfreq_wq (111) can NOT be modified, since it has the PF_NO_SETAFFINITY flag set, but although the affinity mask is 0xff which is NOT ok, the thread is currently running on core 0 which is ok Affinity of watchdogd (112) already is 0x7 which is ok, and the thread is currently running on core 2 which is ok Affinity of kswapd0 (114) already is 0x7 which is ok, and the thread is currently running on core 2 which is ok Affinity of kthrotld (117) can NOT be modified, since it has the PF_NO_SETAFFINITY flag set, but although the affinity mask is 0xff which is NOT ok, the thread is currently running on core 1 which is ok Affinity of acpi_thermal_pm (118) can NOT be modified, since it has the PF_NO_SETAFFINITY flag set, but although the affinity mask is 0xff which is NOT ok, the thread is currently running on core 2 which is ok Affinity of scsi_eh_0 (120) already is 0x7 which is ok, but the thread is currently running on core 3 which is NOT ok Affinity of scsi_tmf_0 (121) can NOT be modified, since it has the PF_NO_SETAFFINITY flag set, but although the affinity mask is 0xff which is NOT ok, the thread is currently running on core 0 which is ok Affinity of scsi_eh_1 (122) already is 0x7 which is ok, and the thread is currently running on core 1 which is ok Affinity of scsi_tmf_1 (123) can NOT be modified, since it has the PF_NO_SETAFFINITY flag set, but although the affinity mask is 0xff which is NOT ok, the thread is currently running on core 1 which is ok Affinity of scsi_eh_2 (124) already is 0x7 which is ok, and the thread is currently running on core 1 which is ok Affinity of scsi_tmf_2 (125) can NOT be modified, since it has the PF_NO_SETAFFINITY flag set, but although the affinity mask is 0xff which is NOT ok, the thread is currently running on core 2 which is ok Affinity of scsi_eh_3 (126) already is 0x7 which is ok, and the thread is currently running on core 2 which is ok Affinity of scsi_tmf_3 (127) can NOT be modified, since it has the PF_NO_SETAFFINITY flag set, but although the affinity mask is 0xff which is NOT ok, the thread is currently running on core 0 which is ok Affinity of scsi_eh_4 (128) already is 0x7 which is ok, and the thread is currently running on core 2 which is ok Affinity of scsi_tmf_4 (129) can NOT be modified, since it has the PF_NO_SETAFFINITY flag set, but although the affinity mask is 0xff which is NOT ok, the thread is currently running on core 1 which is ok Affinity of scsi_eh_5 (130) already is 0x7 which is ok, and the thread is currently running on core 1 which is ok Affinity of scsi_tmf_5 (131) can NOT be modified, since it has the PF_NO_SETAFFINITY flag set, but although the affinity mask is 0xff which is NOT ok, the thread is currently running on core 2 which is ok Affinity of raid5wq (140) can NOT be modified, since it has the PF_NO_SETAFFINITY flag set, and because the affinity mask unfortunately is 0xff which is NOT ok, the thread is running on core 3 which is NOT ok Affinity of dm_bufio_cache (141) can NOT be modified, since it has the PF_NO_SETAFFINITY flag set, and because the affinity mask unfortunately is 0xff which is NOT ok, the thread is running on core 3 which is NOT ok Affinity of ipv6_addrconf (142) can NOT be modified, since it has the PF_NO_SETAFFINITY flag set, and because the affinity mask unfortunately is 0xff which is NOT ok, the thread is running on core 3 which is NOT ok Affinity of printk (200) already is 0x7 which is ok, and the thread is currently running on core 0 which is ok Affinity of e1000e (262) can NOT be modified, since it has the PF_NO_SETAFFINITY flag set, and because the affinity mask unfortunately is 0xff which is NOT ok, the thread is running on core 3 which is NOT ok Affinity of e1000e (266) can NOT be modified, since it has the PF_NO_SETAFFINITY flag set, and because the affinity mask unfortunately is 0xff which is NOT ok, the thread is running on core 3 which is NOT ok Affinity of jbd2/sda2-8 (315) already is 0x7 which is ok, and the thread is currently running on core 2 which is ok Affinity of ext4-rsv-conver (316) can NOT be modified, since it has the PF_NO_SETAFFINITY flag set, and because the affinity mask unfortunately is 0xff which is NOT ok, the thread is running on core 3 which is NOT ok Affinity of firewire (371) can NOT be modified, since it has the PF_NO_SETAFFINITY flag set, and because the affinity mask unfortunately is 0xff which is NOT ok, the thread is running on core 3 which is NOT ok Affinity of rpciod (382) can NOT be modified, since it has the PF_NO_SETAFFINITY flag set, and because the affinity mask unfortunately is 0xff which is NOT ok, the thread is running on core 3 which is NOT ok Affinity of xprtiod (383) can NOT be modified, since it has the PF_NO_SETAFFINITY flag set, and because the affinity mask unfortunately is 0xff which is NOT ok, the thread is running on core 3 which is NOT ok Affinity of jbd2/sda1-8 (492) already is 0x7 which is ok, and the thread is currently running on core 2 which is ok Affinity of ext4-rsv-conver (493) can NOT be modified, since it has the PF_NO_SETAFFINITY flag set, and because the affinity mask unfortunately is 0xff which is NOT ok, the thread is running on core 3 which is NOT ok Affinity of nfsiod (789) can NOT be modified, since it has the PF_NO_SETAFFINITY flag set, and because the affinity mask unfortunately is 0xff which is NOT ok, the thread is running on core 3 which is NOT ok Affinity of NFSv4 callback (6448) can NOT be modified, since it has the PF_NO_SETAFFINITY flag set, and because the affinity mask unfortunately is 0xff which is NOT ok, the thread is running on core 3 which is NOT ok Affinity of kworker/u17:0-xprtiod (10168) can NOT be modified, since it has the PF_NO_SETAFFINITY flag set, but although the affinity mask is 0xf7 which is NOT ok, the thread is currently running on core 2 which is ok Affinity of kworker/u16:1-events_unbound (10894) can NOT be modified, since it has the PF_NO_SETAFFINITY flag set, but although the affinity mask is 0xf7 which is NOT ok, the thread is currently running on core 1 which is ok Affinity of kworker/u16:0-events_unbound (12997) can NOT be modified, since it has the PF_NO_SETAFFINITY flag set, but although the affinity mask is 0xf7 which is NOT ok, the thread is currently running on core 0 which is ok Affinity of kworker/u17:2-xprtiod (19479) can NOT be modified, since it has the PF_NO_SETAFFINITY flag set, but although the affinity mask is 0xf7 which is NOT ok, the thread is currently running on core 1 which is ok Affinity of kworker/u16:2-flush-8:0 (20130) can NOT be modified, since it has the PF_NO_SETAFFINITY flag set, but although the affinity mask is 0xf7 which is NOT ok, the thread is currently running on core 2 which is ok
