lkml.org 
[lkml]   [2007]   [Nov]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [perfmon] Re: [perfmon2] perfmon2 merge news
    Nick Piggin writes:

    > What I really mean is a readv-like syscall, but one that also
    > vectorises the file offset. Maybe this is useful enough as a generic
    > syscall that also helps Paul's example...

    I've sometimes thought it would be useful to have a "transaction"
    system call that is like a write + read combined into one:

    int transaction(int fd, char *req, size_t req_nb,
    char *reply, size_t reply_nb);

    as a way to provide a general request/reply interface for special
    files.

    > Of course, I guess this all depends on whether the atomicity is an
    > important requirement. If not, you can obviously just do it with
    > multiple read syscalls...

    That would take N system calls instead of one, which could have a
    performance impact if you need to read the counters frequently (which
    I believe you do in some performance monitoring situations).

    Paul.
    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2007-11-14 22:55    [W:4.038 / U:0.192 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site