On 2017-11-30 12:51 PM, MMM wrote: > Dear Julien, > > Thanks for your response. Is the mentioned task easier in Java or C program? > indeed, I think it can be easier in Java program. If it is true, I can > switch to Java language.
No, your test program should be in C because it will be easy to link the open()/read() calls from your C program to the open/read system calls. Julien > > On Thursday, November 30, 2017, 7:15:21 PM GMT+3:30, Julien Desfossez > <jdesfos...@efficios.com> wrote: > > > 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