add blktrace_start tool

used to enable blktrace on a block device

git-svn-id: http://ltt.polymtl.ca/svn@2835 04897980-b3bd-0310-b5e0-8ef037075253

diff --git a/blk/Makefile b/blk/Makefile
new file mode 100644 (file)
index 0000000..53363ff
--- /dev/null
+++ b/blk/Makefile
@@ -0,0 +1,2 @@
+blktrace_start: blktrace_start.c
+       gcc -o blktrace_start blktrace_start.c

diff --git a/blk/blktrace_api.h b/blk/blktrace_api.h
new file mode 100644 (file)
index 0000000..61b405a
--- /dev/null
+++ b/blk/blktrace_api.h
@@ -0,0 +1,128 @@
+#ifndef BLKTRACEAPI_H
+#define BLKTRACEAPI_H
+
+#include <asm/types.h>
+
+/*
+ * Trace categories
+ */
+enum {
+       BLK_TC_READ     = 1 << 0,       /* reads */
+       BLK_TC_WRITE    = 1 << 1,       /* writes */
+       BLK_TC_BARRIER  = 1 << 2,       /* barrier */
+       BLK_TC_SYNC     = 1 << 3,       /* sync */
+       BLK_TC_QUEUE    = 1 << 4,       /* queueing/merging */
+       BLK_TC_REQUEUE  = 1 << 5,       /* requeueing */
+       BLK_TC_ISSUE    = 1 << 6,       /* issue */
+       BLK_TC_COMPLETE = 1 << 7,       /* completions */
+       BLK_TC_FS       = 1 << 8,       /* fs requests */
+       BLK_TC_PC       = 1 << 9,       /* pc requests */
+       BLK_TC_NOTIFY   = 1 << 10,      /* special message */
+       BLK_TC_AHEAD    = 1 << 11,      /* readahead */
+       BLK_TC_META     = 1 << 12,      /* metadata */
+
+       BLK_TC_END      = 1 << 15,      /* only 16-bits, reminder */
+};
+
+#define BLK_TC_SHIFT           (16)
+#define BLK_TC_ACT(act)                ((act) << BLK_TC_SHIFT)
+
+/*
+ * Basic trace actions
+ */
+enum {
+       __BLK_TA_QUEUE = 1,             /* queued */
+       __BLK_TA_BACKMERGE,             /* back merged to existing rq */
+       __BLK_TA_FRONTMERGE,            /* front merge to existing rq */
+       __BLK_TA_GETRQ,                 /* allocated new request */
+       __BLK_TA_SLEEPRQ,               /* sleeping on rq allocation */
+       __BLK_TA_REQUEUE,               /* request requeued */
+       __BLK_TA_ISSUE,                 /* sent to driver */
+       __BLK_TA_COMPLETE,              /* completed by driver */
+       __BLK_TA_PLUG,                  /* queue was plugged */
+       __BLK_TA_UNPLUG_IO,             /* queue was unplugged by io */
+       __BLK_TA_UNPLUG_TIMER,          /* queue was unplugged by timer */
+       __BLK_TA_INSERT,                /* insert request */
+       __BLK_TA_SPLIT,                 /* bio was split */
+       __BLK_TA_BOUNCE,                /* bio was bounced */
+       __BLK_TA_REMAP,                 /* bio was remapped */
+};
+
+/*
+ * Notify events.
+ */
+enum blktrace_notify {
+       __BLK_TN_PROCESS = 0,           /* establish pid/name mapping */
+       __BLK_TN_TIMESTAMP,             /* include system clock */
+};
+
+/*
+ * Trace actions in full. Additionally, read or write is masked
+ */
+#define BLK_TA_QUEUE           (__BLK_TA_QUEUE | BLK_TC_ACT(BLK_TC_QUEUE))
+#define BLK_TA_BACKMERGE       (__BLK_TA_BACKMERGE | BLK_TC_ACT(BLK_TC_QUEUE))
+#define BLK_TA_FRONTMERGE      (__BLK_TA_FRONTMERGE | BLK_TC_ACT(BLK_TC_QUEUE))
+#define        BLK_TA_GETRQ            (__BLK_TA_GETRQ | BLK_TC_ACT(BLK_TC_QUEUE))
+#define        BLK_TA_SLEEPRQ          (__BLK_TA_SLEEPRQ | BLK_TC_ACT(BLK_TC_QUEUE))
+#define        BLK_TA_REQUEUE          (__BLK_TA_REQUEUE | BLK_TC_ACT(BLK_TC_REQUEUE))
+#define BLK_TA_ISSUE           (__BLK_TA_ISSUE | BLK_TC_ACT(BLK_TC_ISSUE))
+#define BLK_TA_COMPLETE                (__BLK_TA_COMPLETE| BLK_TC_ACT(BLK_TC_COMPLETE))
+#define BLK_TA_PLUG            (__BLK_TA_PLUG | BLK_TC_ACT(BLK_TC_QUEUE))
+#define BLK_TA_UNPLUG_IO       (__BLK_TA_UNPLUG_IO | BLK_TC_ACT(BLK_TC_QUEUE))
+#define BLK_TA_UNPLUG_TIMER    (__BLK_TA_UNPLUG_TIMER | BLK_TC_ACT(BLK_TC_QUEUE))
+#define BLK_TA_INSERT          (__BLK_TA_INSERT | BLK_TC_ACT(BLK_TC_QUEUE))
+#define BLK_TA_SPLIT           (__BLK_TA_SPLIT)
+#define BLK_TA_BOUNCE          (__BLK_TA_BOUNCE)
+#define BLK_TA_REMAP           (__BLK_TA_REMAP | BLK_TC_ACT(BLK_TC_QUEUE))
+
+#define BLK_TN_PROCESS         (__BLK_TN_PROCESS | BLK_TC_ACT(BLK_TC_NOTIFY))
+#define BLK_TN_TIMESTAMP       (__BLK_TN_TIMESTAMP | BLK_TC_ACT(BLK_TC_NOTIFY))
+
+#define BLK_IO_TRACE_MAGIC     0x65617400
+#define BLK_IO_TRACE_VERSION   0x07
+
+/*
+ * The trace itself
+ */
+struct blk_io_trace {
+       __u32 magic;            /* MAGIC << 8 | version */
+       __u32 sequence;         /* event number */
+       __u64 time;             /* in nanoseconds */
+       __u64 sector;           /* disk offset */
+       __u32 bytes;            /* transfer length */
+       __u32 action;           /* what happened */
+       __u32 pid;              /* who did it */
+       __u32 device;           /* device identifier (dev_t) */
+       __u32 cpu;              /* on what cpu did it happen */
+       __u16 error;            /* completion error */
+       __u16 pdu_len;          /* length of data after this trace */
+};
+
+/*
+ * The remap event
+ */
+struct blk_io_trace_remap {
+       __u32 device;
+       __u32 device_from;
+       __u64 sector;
+};
+
+/*
+ * User setup structure passed with BLKSTARTTRACE
+ */
+struct blk_user_trace_setup {
+       char name[32];                  /* output */
+       __u16 act_mask;                 /* input */
+       __u32 buf_size;                 /* input */
+       __u32 buf_nr;                   /* input */
+       __u64 start_lba;
+       __u64 end_lba;
+       __u32 pid;
+};
+
+#define BLKTRACESETUP _IOWR(0x12,115,struct blk_user_trace_setup)
+#define BLKTRACESTART _IO(0x12,116)
+#define BLKTRACESTOP _IO(0x12,117)
+#define BLKTRACETEARDOWN _IO(0x12,118)
+
+#endif

diff --git a/blk/blktrace_start.c b/blk/blktrace_start.c
new file mode 100644 (file)
index 0000000..97c1592
--- /dev/null
+++ b/blk/blktrace_start.c
@@ -0,0 +1,59 @@
+#include <sys/types.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/ioctl.h>
+#include <string.h>
+#include <stdio.h>
+
+#include "blktrace_api.h"
+
+int start(int fd)
+{
+       struct blk_user_trace_setup buts;
+
+       memset(&buts, 0, sizeof(buts));
+       buts.buf_size = 512*1024;
+       buts.buf_nr = 4;
+       buts.act_mask = ~0;
+
+       if (ioctl(fd, BLKTRACESETUP, &buts) < 0) {
+               perror("BLKTRACESETUP");
+               return 1;
+       }
+
+       return 0;
+}
+
+int stop(int fd)
+{
+       ioctl(fd, BLKTRACESTOP);
+       if(ioctl(fd, BLKTRACETEARDOWN) < 0)
+               perror("BLKTRACETEARDOWN");
+
+       return 0;
+}
+
+int main(int argc, char **argv)
+{
+       int fd;
+
+       if(argc < 3) {
+               fprintf(stderr, "usage: --start|--stop %s BLKDEV\n", argv[0]);
+               return 1;
+       }
+
+       fd = open(argv[2], O_RDONLY | O_NONBLOCK);
+       if (fd < 0) {
+               perror(argv[1]);
+               return 1;
+       }
+
+       if(!strcmp("--start", argv[1]))
+               start(fd);
+       else if(!strcmp("--stop", argv[1]))
+               stop(fd);
+
+       close(fd);
+
+       return 0;
+}