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correctly calculate writeout bandwidth and properly impose limits

This commit is contained in:
Vincent Sanders 2014-11-29 23:56:33 +00:00
parent 70e777c30d
commit d08acbc5ae
2 changed files with 66 additions and 19 deletions
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3
content/fs_backing_store.c
View File

@ -1230,6 +1230,9 @@ initialise(const struct llcache_store_parameters *parameters)
/**
* Finalise the backing store.
*
* \todo This will cause the backing store to leak any outstanding memory
* allocations. This will probably best be done by a global use count.
*
* @return NSERROR_OK on success.
*/
static nserror

82
content/llcache.c
View File

@ -2262,7 +2262,7 @@ build_candidate_list(struct llcache_object ***lst_out, int *lst_len_out)
int lst_len = 0;
int remaining_lifetime;
#define MAX_PERSIST_PER_RUN 512
#define MAX_PERSIST_PER_RUN 128
lst = calloc(MAX_PERSIST_PER_RUN, sizeof(struct llcache_object *));
if (lst == NULL) {
@ -2379,14 +2379,18 @@ write_backing_store(struct llcache_object *object,
static void llcache_persist(void *p)
{
nserror ret;
size_t size_written;
size_t total_written = 0;
struct llcache_object **lst;
int lst_count;
int idx;
unsigned long write_limit; /* max number of bytes to write */
unsigned long total_elapsed = 1;
unsigned long elapsed;
struct llcache_object **lst; /* candidate object list */
int lst_count; /* number of candidates in list */
int idx; /* current candidate object index in list */
unsigned long write_limit; /* max number of bytes to write in this run*/
size_t written; /* all bytes written for a single object */
unsigned long elapsed; /* how long writing an object took */
size_t total_written = 0; /* total bytes written in this run */
unsigned long total_elapsed = 1; /* total ms used to write bytes */
unsigned long total_bandwidth = 0; /* total bandwidth */
ret = build_candidate_list(&lst, &lst_count);
if (ret != NSERROR_OK) {
@ -2398,28 +2402,68 @@ static void llcache_persist(void *p)
/* obtained a candidate list, make each object persistant in turn */
for (idx = 0; idx < lst_count; idx++) {
ret = write_backing_store(lst[idx], &size_written, &elapsed);
ret = write_backing_store(lst[idx], &written, &elapsed);
if (ret == NSERROR_OK) {
/* sucessfully wrote object to backing store */
total_written += size_written;
total_written += written;
total_elapsed += elapsed;
LOG(("Wrote %d bytes in %dms %s",
size_written,
elapsed,
total_bandwidth = (total_written * 1000) / total_elapsed;
LOG(("Wrote %d bytes in %dms bw:%d %s",
written, elapsed, (written * 1000) / elapsed,
nsurl_access(lst[idx]->url) ));
if (total_written > write_limit) {
/* The bandwidth limit has been reached.
* Writeout scheduled for the remaining objects
/* check to for the time quantum or the size
* (bandwidth) for this run being exceeded.
*/
if (total_elapsed > llcache->time_quantum) {
/* writeout has exhausted the available time.
* Either the writeout is slow or the last
* object was very large.
*/
guit->browser->schedule(llcache->time_quantum, llcache_persist, NULL);
if (total_bandwidth < llcache->minimum_bandwidth) {
LOG(("Cannot write minimum bandwidth"));
warn_user("Disc cache write bandwidth is too slow to be useful, disabling cache", 0);
guit->llcache->finalise();
break;
} else {
unsigned long next;
if (total_bandwidth > llcache->maximum_bandwidth) {
/* fast writeout of large file
* so calculate delay as if
* write happened only at max
* limit
*/
next = ((total_written * llcache->time_quantum) / write_limit) - total_elapsed;
} else {
next = llcache->time_quantum;
}
LOG(("Overran our timeslot Rescheduling writeout in %dms", next));
guit->browser->schedule(next,
llcache_persist, NULL);
break;
}
} else if (total_written > write_limit) {
/* The bandwidth limit has been reached. */
unsigned long next;
if (total_bandwidth > llcache->maximum_bandwidth) {
/* fast writeout of large file so
* calculate delay as if write
* happened only at max limit
*/
next = ((total_written * llcache->time_quantum) / write_limit) - total_elapsed;
} else {
next = llcache->time_quantum - total_elapsed;
}
LOG(("Rescheduling writeout in %dms", next));
guit->browser->schedule(next, llcache_persist,
NULL);
break;
}
}
}
LOG(("writeout size:%d time:%d bandwidth:%dbytes/s",
total_written, total_elapsed, (total_written * 1000) / total_elapsed));
total_written, total_elapsed, total_bandwidth));
free(lst);
}