On 2017-11-30 10:13 AM, MMM via lttng-dev wrote: > Dear Users, > > I have posted a couple of email about my problem in the past, while > nobody response those. It may be true that my question is amateurish, > but due to the fact that I am a beginner, I can not find the sufficient > document for solving my problem. I am going to trace a C program that > read from a file and show the ratio of reads from page cache vs reads > from disk. I read document of LTTng website, but I can not find > appropriate explanation for this task. I just need a simple guidance to > show me the right way for doing it. Could you please help me. > > Regards, > Mehdi.
Hi, This is a really non-trivial task to do. Basically, you need to distinguish the read() syscalls that lead to FS/disk access with the ones that don't (for the same FD). The main difficulty is to make the link between the syscall and the lower-level events and I am not sure we have all the data needed to establish this link from the payload of the events we have (something like FD -> FS inode -> block). I added Houssem to this thread because I think I remember he did some work around that, he may have more information. Julien _______________________________________________ lttng-dev mailing list lttng-dev@lists.lttng.org https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev