lkml.org 
[lkml]   [2010]   [Feb]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    From
    Subject[PATCH 08/11] readahead: add tracing event
    Example output:

    # echo 1 > /debug/tracing/events/readahead/enable
    # cp test-file /dev/null
    # cat /debug/tracing/trace # trimmed output
    readahead-initial(dev=0:15, ino=100177, req=0+2, ra=0+4-2, async=0) = 4
    readahead-subsequent(dev=0:15, ino=100177, req=2+2, ra=4+8-8, async=1) = 8
    readahead-subsequent(dev=0:15, ino=100177, req=4+2, ra=12+16-16, async=1) = 16
    readahead-subsequent(dev=0:15, ino=100177, req=12+2, ra=28+32-32, async=1) = 32
    readahead-subsequent(dev=0:15, ino=100177, req=28+2, ra=60+60-60, async=1) = 24
    readahead-subsequent(dev=0:15, ino=100177, req=60+2, ra=120+60-60, async=1) = 0

    CC: Ingo Molnar <mingo@elte.hu>
    CC: Jens Axboe <jens.axboe@oracle.com>
    CC: Peter Zijlstra <a.p.zijlstra@chello.nl>
    Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
    ---
    include/trace/events/readahead.h | 69 +++++++++++++++++++++++++++++
    mm/readahead.c | 22 +++++++++
    2 files changed, 91 insertions(+)

    --- /dev/null 1970-01-01 00:00:00.000000000 +0000
    +++ linux/include/trace/events/readahead.h 2010-02-01 21:58:48.000000000 +0800
    @@ -0,0 +1,69 @@
    +#undef TRACE_SYSTEM
    +#define TRACE_SYSTEM readahead
    +
    +#if !defined(_TRACE_READAHEAD_H) || defined(TRACE_HEADER_MULTI_READ)
    +#define _TRACE_READAHEAD_H
    +
    +#include <linux/tracepoint.h>
    +
    +extern const char * const ra_pattern_names[];
    +
    +/*
    + * Tracepoint for guest mode entry.
    + */
    +TRACE_EVENT(readahead,
    + TP_PROTO(struct address_space *mapping,
    + pgoff_t offset,
    + unsigned long req_size,
    + unsigned int ra_flags,
    + pgoff_t start,
    + unsigned int size,
    + unsigned int async_size,
    + unsigned int actual),
    +
    + TP_ARGS(mapping, offset, req_size,
    + ra_flags, start, size, async_size, actual),
    +
    + TP_STRUCT__entry(
    + __field( dev_t, dev )
    + __field( ino_t, ino )
    + __field( pgoff_t, offset )
    + __field( unsigned long, req_size )
    + __field( unsigned int, pattern )
    + __field( pgoff_t, start )
    + __field( unsigned int, size )
    + __field( unsigned int, async_size )
    + __field( unsigned int, actual )
    + ),
    +
    + TP_fast_assign(
    + __entry->dev = mapping->host->i_sb->s_dev;
    + __entry->ino = mapping->host->i_ino;
    + __entry->pattern = ra_pattern(ra_flags);
    + __entry->offset = offset;
    + __entry->req_size = req_size;
    + __entry->start = start;
    + __entry->size = size;
    + __entry->async_size = async_size;
    + __entry->actual = actual;
    + ),
    +
    + TP_printk("readahead-%s(dev=%d:%d, ino=%lu, "
    + "req=%lu+%lu, ra=%lu+%d-%d, async=%d) = %d",
    + ra_pattern_names[__entry->pattern],
    + MAJOR(__entry->dev),
    + MINOR(__entry->dev),
    + __entry->ino,
    + __entry->offset,
    + __entry->req_size,
    + __entry->start,
    + __entry->size,
    + __entry->async_size,
    + __entry->start > __entry->offset,
    + __entry->actual)
    +);
    +
    +#endif /* _TRACE_READAHEAD_H */
    +
    +/* This part must be outside protection */
    +#include <trace/define_trace.h>
    --- linux.orig/mm/readahead.c 2010-02-01 21:55:43.000000000 +0800
    +++ linux/mm/readahead.c 2010-02-01 21:57:25.000000000 +0800
    @@ -19,11 +19,25 @@
    #include <linux/pagevec.h>
    #include <linux/pagemap.h>

    +#define CREATE_TRACE_POINTS
    +#include <trace/events/readahead.h>
    +
    /*
    * Set async size to 1/# of the thrashing threshold.
    */
    #define READAHEAD_ASYNC_RATIO 8

    +const char * const ra_pattern_names[] = {
    + [RA_PATTERN_INITIAL] = "initial",
    + [RA_PATTERN_SUBSEQUENT] = "subsequent",
    + [RA_PATTERN_CONTEXT] = "context",
    + [RA_PATTERN_THRASH] = "thrash",
    + [RA_PATTERN_MMAP_AROUND] = "around",
    + [RA_PATTERN_FADVISE] = "fadvise",
    + [RA_PATTERN_RANDOM] = "random",
    + [RA_PATTERN_ALL] = "all",
    +};
    +
    /*
    * Initialise a struct file's readahead state. Assumes that the caller has
    * memset *ra to zero.
    @@ -274,6 +288,11 @@ int force_page_cache_readahead(struct ad
    offset += this_chunk;
    nr_to_read -= this_chunk;
    }
    +
    + trace_readahead(mapping, offset, nr_to_read,
    + RA_PATTERN_FADVISE << READAHEAD_PATTERN_SHIFT,
    + offset, nr_to_read, 0, ret);
    +
    return ret;
    }

    @@ -301,6 +320,9 @@ unsigned long ra_submit(struct file_ra_s
    actual = __do_page_cache_readahead(mapping, filp,
    ra->start, ra->size, ra->async_size);

    + trace_readahead(mapping, offset, req_size, ra->ra_flags,
    + ra->start, ra->size, ra->async_size, actual);
    +
    return actual;
    }




    \
     
     \ /
      Last update: 2010-02-02 16:39    [W:0.040 / U:122.848 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site