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On Mon 18-03-19 13:28:50, Pankaj Suryawanshi wrote: > On Mon 18-03-19 12:58:28, Pankaj Suryawanshi wrote: > > > Hello, > > > > > > I am facing issue of high latency in CMA allocation of large size buffer. > > > > > > I am frequently allocating/deallocation CMA memory, latency of allocation > > > is very high. > > > > > > Below are the stat for allocation/deallocation latency issue. > > > > > > (390100 kB), latency 29997 us > > > (390100 kB), latency 22957 us > > > (390100 kB), latency 25735 us > > > (390100 kB), latency 12736 us > > > (390100 kB), latency 26009 us > > > (390100 kB), latency 18058 us > > > (390100 kB), latency 27997 us > > > (16 kB), latency 560 us > > > (256 kB), latency 280 us > > > (4 kB), latency 311 us > > > > > > I am using kernel 4.14.65 with android pie(9.0). > > > > > > Is there any workaround or solution for this(cma_alloc latency) issue ? > > > > Do you have any more detailed information on where the time is spent? > > E.g. migration tracepoints? > > > > Hello Michal, > > I have the system(vanilla kernel) with 2GB of RAM, reserved 1GB for CMA. No > swap or zram. > Sorry, I don't have information where the time is spent. > time is calculated in between cma_alloc call. > I have just cma_alloc trace information/function graph. Then please collect that data because it is really hard to judge anything from the numbers you have provided. -- Michal Hocko SUSE Labs
