On Sun, Jan 31, 2021 at 05:16:47PM +0800, Weiping Zhang wrote: > On Wed, Jan 27, 2021 at 7:13 PM Balbir Singh <bsinghar...@gmail.com> wrote: > > > > On Fri, Jan 22, 2021 at 10:07:50PM +0800, Weiping Zhang wrote: > > > Hello Balbir Singh, > > > > > > Could you help review this patch, thanks > > > > > > On Mon, Dec 28, 2020 at 10:10 PM Weiping Zhang <zwp10...@gmail.com> wrote: > > > > > > > > Hi David, > > > > > > > > Could you help review this patch ? > > > > > > > > thanks > > > > > > > > On Fri, Dec 18, 2020 at 1:24 AM Weiping Zhang > > > > <zhangweip...@didiglobal.com> wrote: > > > > > > > > > > If a program needs monitor lots of process's status, it needs two > > > > > syscalls for every process. The first one is telling kernel which > > > > > pid/tgid should be monitored by send a command(write socket) to > > > > > kernel. > > > > > The second one is read the statistics by read socket. This patch add > > > > > a new interface /proc/taskstats to reduce two syscalls to one ioctl. > > > > > The user just set the target pid/tgid to the struct taskstats.ac_pid, > > > > > then kernel will collect statistics for that pid/tgid. > > > > > > > > > > Signed-off-by: Weiping Zhang <zhangweip...@didiglobal.com> > > > > Could you elaborate on the overhead your seeing for the syscalls? I am not > > in favour of adding new IOCTL's. > > > > Balbir Singh. > > Hello Balbir Singh, > > Sorry for late reply, > > I do a performance test between netlink mode and ioctl mode, > monitor 1000 and 10000 sleep processes, > the netlink mode cost more time than ioctl mode, that is to say > ioctl mode can save some cpu resource and has a quickly reponse > especially when monitor lot of process. > > proccess-count netlink ioctl > --------------------------------------------- > 1000 0.004446851 0.001553733 > 10000 0.047024986 0.023290664 > > you can get the test demo code from the following link > https://github.com/dublio/tools/tree/master/c/taskstat >
Let me try it out, I am opposed to adding the new IOCTL interface you propose. How frequently do you monitor this data and how much time in spent in making decision on the data? I presume the data mentioned is the cost per call in seconds? Balbir Singh
