fd4c2b74f3
The implementation is in libblockdriver, and works transparently for all block drivers. The new btrace(8) tool can be used to control block tracing; see ``man btrace'' for details.
284 lines
6.5 KiB
C
284 lines
6.5 KiB
C
/* This file implements block level tracing support. */
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#include <minix/drivers.h>
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#include <minix/blockdriver_mt.h>
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#include <minix/btrace.h>
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#include <sys/ioc_block.h>
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#include <minix/minlib.h>
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#include <assert.h>
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#include "trace.h"
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#define NO_TRACEDEV ((dev_t) -1)
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#define NO_TIME ((u32_t) -1)
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PRIVATE int trace_enabled = FALSE;
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PRIVATE dev_t trace_dev = NO_TRACEDEV;
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PRIVATE btrace_entry *trace_buf = NULL;
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PRIVATE size_t trace_size = 0;
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PRIVATE size_t trace_pos;
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PRIVATE size_t trace_next;
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PRIVATE u64_t trace_tsc;
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/* Pointers to in-progress trace entries for each thread (all worker threads,
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* plus one for the main thread). Each pointer is set to NULL whenever no
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* operation is currently being traced for that thread, for whatever reason.
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*/
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PRIVATE btrace_entry *trace_ptr[BLOCKDRIVER_MT_MAX_WORKERS + 1] = { NULL };
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/*===========================================================================*
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* trace_gettime *
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*===========================================================================*/
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PRIVATE u32_t trace_gettime(void)
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{
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/* Return the current time, in microseconds since the start of the trace.
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*/
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u64_t tsc;
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assert(trace_enabled);
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read_tsc_64(&tsc);
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tsc = sub64(tsc, trace_tsc);
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return tsc_64_to_micros(tsc);
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}
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/*===========================================================================*
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* trace_ctl *
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*===========================================================================*/
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PUBLIC int trace_ctl(dev_t minor, unsigned int request, endpoint_t endpt,
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cp_grant_id_t grant)
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{
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/* Process a block trace control request.
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*/
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size_t size;
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int r, ctl, entries;
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switch (request) {
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case BIOCTRACEBUF:
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/* The size cannot be changed when tracing is enabled. */
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if (trace_enabled) return EBUSY;
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/* Copy in the requested size. */
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if ((r = sys_safecopyfrom(endpt, grant, 0, (vir_bytes) &size,
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sizeof(size), D)) != OK)
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return r;
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if (size >= INT_MAX / sizeof(btrace_entry)) return EINVAL;
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/* The size can only be set or reset, not changed. */
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if (size > 0 && trace_size > 0) return EBUSY;
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/* Allocate or free a buffer for tracing data. For future multi-device
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* tracing support, the buffer is associated with a minor device.
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*/
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if (size == 0) {
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if (trace_dev == NO_TRACEDEV) return OK;
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if (trace_dev != minor) return EINVAL;
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free(trace_buf);
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trace_dev = NO_TRACEDEV;
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} else {
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if ((trace_buf = malloc(size * sizeof(btrace_entry))) == NULL)
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return errno;
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trace_dev = minor;
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}
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trace_size = size;
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trace_pos = 0;
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trace_next = 0;
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return OK;
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case BIOCTRACECTL:
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/* We can only start/stop tracing if the given device has a trace
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* buffer associated with it.
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*/
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if (trace_dev != minor) return EINVAL;
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/* Copy in the request code. */
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if ((r = sys_safecopyfrom(endpt, grant, 0, (vir_bytes) &ctl,
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sizeof(ctl), D)) != OK)
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return r;
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/* Start or stop tracing. */
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switch (ctl) {
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case BTCTL_START:
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if (trace_enabled) return EBUSY;
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read_tsc_64(&trace_tsc);
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trace_enabled = TRUE;
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break;
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case BTCTL_STOP:
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if (!trace_enabled) return EINVAL;
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trace_enabled = FALSE;
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/* Cancel all ongoing trace operations. */
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memset(trace_ptr, 0, sizeof(trace_ptr));
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break;
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default:
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return EINVAL;
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}
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return OK;
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case BIOCTRACEGET:
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/* We can only retrieve tracing entries if the given device has a trace
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* buffer associated with it.
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*/
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if (trace_dev != minor) return EINVAL;
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if (trace_enabled) return EBUSY;
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/* How much can we copy out? */
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entries = MIN(trace_pos - trace_next,
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_MINIX_IOCTL_SIZE_BIG(request) / sizeof(btrace_entry));
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if (entries == 0)
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return 0;
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if ((r = sys_safecopyto(endpt, grant, 0,
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(vir_bytes) &trace_buf[trace_next],
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entries * sizeof(btrace_entry), D)) != OK)
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return r;
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trace_next += entries;
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return entries;
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}
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return EINVAL;
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}
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/*===========================================================================*
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* trace_start *
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*===========================================================================*/
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PUBLIC void trace_start(thread_id_t id, message *m_ptr)
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{
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/* Start creating a trace entry.
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*/
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btrace_entry *entry;
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int req;
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u64_t pos;
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size_t size;
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int flags;
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if (!trace_enabled || trace_dev != m_ptr->BDEV_MINOR) return;
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assert(id >= 0 && id < BLOCKDRIVER_MT_MAX_WORKERS + 1);
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if (trace_pos == trace_size)
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return;
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switch (m_ptr->m_type) {
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case BDEV_OPEN: req = BTREQ_OPEN; break;
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case BDEV_CLOSE: req = BTREQ_CLOSE; break;
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case BDEV_READ: req = BTREQ_READ; break;
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case BDEV_WRITE: req = BTREQ_WRITE; break;
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case BDEV_GATHER: req = BTREQ_GATHER; break;
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case BDEV_SCATTER: req = BTREQ_SCATTER; break;
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case BDEV_IOCTL: req = BTREQ_IOCTL; break;
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default: return;
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}
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switch (m_ptr->m_type) {
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case BDEV_OPEN:
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case BDEV_CLOSE:
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pos = cvu64(0);
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size = m_ptr->BDEV_ACCESS;
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flags = 0;
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break;
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case BDEV_READ:
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case BDEV_WRITE:
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case BDEV_GATHER:
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case BDEV_SCATTER:
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pos = make64(m_ptr->BDEV_POS_LO, m_ptr->BDEV_POS_HI);
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size = m_ptr->BDEV_COUNT;
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flags = m_ptr->BDEV_FLAGS;
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break;
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case BDEV_IOCTL:
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pos = cvu64(0);
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size = m_ptr->BDEV_REQUEST;
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flags = 0;
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/* Do not log trace control requests. */
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switch (size) {
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case BIOCTRACEBUF:
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case BIOCTRACECTL:
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case BIOCTRACEGET:
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return;
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}
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break;
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default:
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/* Do not log any other messages. */
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return;
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}
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entry = &trace_buf[trace_pos];
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entry->request = req;
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entry->size = size;
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entry->position = pos;
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entry->flags = flags;
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entry->result = BTRES_INPROGRESS;
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entry->start_time = trace_gettime();
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entry->finish_time = NO_TIME;
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trace_ptr[id] = entry;
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trace_pos++;
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}
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/*===========================================================================*
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* trace_setsize *
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*===========================================================================*/
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PUBLIC void trace_setsize(thread_id_t id, size_t size)
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{
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/* Set the current trace entry's actual (byte) size, for vector requests.
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*/
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btrace_entry *entry;
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if (!trace_enabled) return;
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assert(id >= 0 && id < BLOCKDRIVER_MT_MAX_WORKERS + 1);
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if ((entry = trace_ptr[id]) == NULL) return;
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entry->size = size;
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}
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/*===========================================================================*
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* trace_finish *
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*===========================================================================*/
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PUBLIC void trace_finish(thread_id_t id, int result)
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{
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/* Finish a trace entry.
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*/
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btrace_entry *entry;
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if (!trace_enabled) return;
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assert(id >= 0 && id < BLOCKDRIVER_MT_MAX_WORKERS + 1);
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if ((entry = trace_ptr[id]) == NULL) return;
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entry->result = result;
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entry->finish_time = trace_gettime();
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trace_ptr[id] = NULL;
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}
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