From: wangyong <wang.yong12@xxxxxxxxxx> Add thrashing page cache and direct compact related descriptions and update the usage of getdelays userspace utility. The following patches modifications have been updated: https://lore.kernel.org/all/20190312102002.31737-4-jinpuwang@xxxxxxxxx/ https://lore.kernel.org/all/1638619795-71451-1-git-send-email- wang.yong12@xxxxxxxxxx/ Reported-by: Zeal Robot <zealci@xxxxxxxxxx> Signed-off-by: wangyong <wang.yong12@xxxxxxxxxx> Reviewed-by: Yang Yang <yang.yang29@xxxxxxxxxx> --- Documentation/accounting/delay-accounting.rst | 55 +++++++++++++-------------- 1 file changed, 27 insertions(+), 28 deletions(-) diff --git a/Documentation/accounting/delay-accounting.rst b/Documentation/accounting/delay-accounting.rst index 1b8b46d..197fe31 100644 --- a/Documentation/accounting/delay-accounting.rst +++ b/Documentation/accounting/delay-accounting.rst @@ -13,6 +13,8 @@ a) waiting for a CPU (while being runnable) b) completion of synchronous block I/O initiated by the task c) swapping in pages d) memory reclaim +e) thrashing page cache +f) direct compact and makes these statistics available to userspace through the taskstats interface. @@ -41,11 +43,12 @@ generic data structure to userspace corresponding to per-pid and per-tgid statistics. The delay accounting functionality populates specific fields of this structure. See - include/linux/taskstats.h + include/uapi/linux/taskstats.h for a description of the fields pertaining to delay accounting. It will generally be in the form of counters returning the cumulative -delay seen for cpu, sync block I/O, swapin, memory reclaim etc. +delay seen for cpu, sync block I/O, swapin, memory reclaim, thrash page +cache, direct compact etc. Taking the difference of two successive readings of a given counter (say cpu_delay_total) for a task will give the delay @@ -88,41 +91,37 @@ seen. General format of the getdelays command:: - getdelays [-t tgid] [-p pid] [-c cmd...] - + getdelays [-dilv] [-t tgid] [-p pid] Get delays, since system boot, for pid 10:: - # ./getdelays -p 10 + # ./getdelays -d -p 10 (output similar to next case) Get sum of delays, since system boot, for all pids with tgid 5:: - # ./getdelays -t 5 - - - CPU count real total virtual total delay total - 7876 92005750 100000000 24001500 - IO count delay total - 0 0 - SWAP count delay total - 0 0 - RECLAIM count delay total - 0 0 + # ./getdelays -d -t 5 + print delayacct stats ON + TGID 5 -Get delays seen in executing a given simple command:: - # ./getdelays -c ls / + CPU count real total virtual total delay total delay average + 8 7000000 6872122 3382277 0.423ms + IO count delay total delay average + 0 0 0ms + SWAP count delay total delay average + 0 0 0ms + RECLAIM count delay total delay average + 0 0 0ms + THRASHING count delay total delay average + 0 0 0ms + COMPACT count delay total delay average + 0 0 0ms - bin data1 data3 data5 dev home media opt root srv sys usr - boot data2 data4 data6 etc lib mnt proc sbin subdomain tmp var +Get IO accounting for pid 1, it works only with -p:: + # ./getdelays -i -p 1 + printing IO accounting + linuxrc: read=65536, write=0, cancelled_write=0 - CPU count real total virtual total delay total - 6 4000250 4000000 0 - IO count delay total - 0 0 - SWAP count delay total - 0 0 - RECLAIM count delay total - 0 0 +The above command can be used with -v to get more debug information. -- 2.7.4
