Messages in this thread | | | From | Ganesh Mahendran <> | Date | Mon, 13 Jun 2016 13:13:57 +0800 | Subject | Re: [PATCH] mm/zsmalloc: add trace events for zs_compact |
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2016-06-13 12:42 GMT+08:00 Minchan Kim <minchan@kernel.org>: > On Wed, Jun 08, 2016 at 02:39:19PM +0800, Ganesh Mahendran wrote: > > <snip> > >> zsmalloc is not only used by zram, but also zswap. Maybe >> others in the future. >> >> I tried to use function_graph. It seems there are too much log >> printed: >> ------ >> root@leo-test:/sys/kernel/debug/tracing# cat trace >> # tracer: function_graph >> # >> # CPU DURATION FUNCTION CALLS >> # | | | | | | | >> 2) | zs_compact [zsmalloc]() { >> 2) | /* zsmalloc_compact_start: pool zram0 */ >> 2) 0.889 us | _raw_spin_lock(); >> 2) 0.896 us | isolate_zspage [zsmalloc](); >> 2) 0.938 us | _raw_spin_lock(); >> 2) 0.875 us | isolate_zspage [zsmalloc](); >> 2) 0.942 us | _raw_spin_lock(); >> 2) 0.962 us | isolate_zspage [zsmalloc](); >> ... >> 2) 0.879 us | insert_zspage [zsmalloc](); >> 2) 4.520 us | } >> 2) 0.975 us | _raw_spin_lock(); >> 2) 0.890 us | isolate_zspage [zsmalloc](); >> 2) 0.882 us | _raw_spin_lock(); >> 2) 0.894 us | isolate_zspage [zsmalloc](); >> 2) | /* zsmalloc_compact_end: pool zram0: 0 pages >> compacted(total 0) */ >> 2) # 1351.241 us | } >> ------ >> => 1351.241 us used >> >> And it seems the overhead of function_graph is bigger than trace event. >> >> bash-3682 [002] .... 1439.180646: zsmalloc_compact_start: pool zram0 >> bash-3682 [002] .... 1439.180659: zsmalloc_compact_end: pool zram0: >> 0 pages compacted(total 0) >> => 13 us > 1351.241 us > > You could use to cut out. > > To introduce new event trace to get a elasped time, it's pointless, > I think.
Agree.
> > It should have more like pool name you mentioned. > Like saying other thread, It would be better to show > [pool name, compact size_class, > the number of object moved, the number of freed page], IMO.
Thanks for you suggestion! I would be useful to see compact details for each class. I will send another patch to do this.
Thanks.
> > Thanks.
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