Messages in this thread Patch in this message | | | Date | Wed, 15 Aug 2018 10:48:25 +0200 | From | Jiri Olsa <> | Subject | Re: [PATCH] perf tools: Add struct ordered_events_buffer layer |
| |
On Tue, Aug 14, 2018 at 12:14:19AM -0700, Stephane Eranian wrote:
SNIP
> > @@ -104,11 +110,12 @@ static struct ordered_event *alloc_event(struct ordered_events *oe, > > new = list_entry(cache->next, struct ordered_event, list); > > list_del(&new->list); > > } else if (oe->buffer) { > > - new = oe->buffer + oe->buffer_idx; > > + new = &oe->buffer->event[oe->buffer_idx]; > > if (++oe->buffer_idx == MAX_SAMPLE_BUFFER) > > oe->buffer = NULL; > > } else if (oe->cur_alloc_size < oe->max_alloc_size) { > > - size_t size = MAX_SAMPLE_BUFFER * sizeof(*new); > > + size_t size = sizeof(*oe->buffer) + > > + MAX_SAMPLE_BUFFER * sizeof(*new); > > > > oe->buffer = malloc(size); > > if (!oe->buffer) { > > @@ -122,9 +129,8 @@ static struct ordered_event *alloc_event(struct ordered_events *oe, > > oe->cur_alloc_size += size; > > list_add(&oe->buffer->list, &oe->to_free); > > > > - /* First entry is abused to maintain the to_free list. */ > > - oe->buffer_idx = 2; > > - new = oe->buffer + 1; > > + oe->buffer_idx = 1; > > + new = &oe->buffer->event[0]; > > Ok, but I think this section between the malloc() and the line above > needs some comments to clarify what is going on. > It is still hard to read.
ok, I put some bigger comment at the top, but I'm not too happy feel free to suggest different one ;-)
> > > } else { > > pr("allocation limit reached %" PRIu64 "B\n", oe->max_alloc_size); > > } > > @@ -300,15 +306,27 @@ void ordered_events__init(struct ordered_events *oe, ordered_events__deliver_t d > > oe->deliver = deliver; > > } > > > > +static void > > +ordered_events_buffer__free(struct ordered_events_buffer *buffer, > > + struct ordered_events *oe) > > +{ > > + if (oe->copy_on_queue) { > > + unsigned int i; > > + > > + for (i = 0; i < MAX_SAMPLE_BUFFER; i++) > > + __free_dup_event(oe, buffer->event[i].event); > > + } > > + > I have a problem with this one, given that the buffer->event[] is > never actually zeroed. > So what happens if you do not use all the entries by the time you have to free? > I think one way to avoid this is by iterating only all the way to > oe->buffer_idx.
right, please check attached patch
thanks, jirka
--- diff --git a/tools/perf/util/ordered-events.c b/tools/perf/util/ordered-events.c index bad9e0296e9a..7a9707301f17 100644 --- a/tools/perf/util/ordered-events.c +++ b/tools/perf/util/ordered-events.c @@ -80,14 +80,20 @@ static union perf_event *dup_event(struct ordered_events *oe, return oe->copy_on_queue ? __dup_event(oe, event) : event; } -static void free_dup_event(struct ordered_events *oe, union perf_event *event) +static void __free_dup_event(struct ordered_events *oe, union perf_event *event) { - if (event && oe->copy_on_queue) { + if (event) { oe->cur_alloc_size -= event->header.size; free(event); } } +static void free_dup_event(struct ordered_events *oe, union perf_event *event) +{ + if (oe->copy_on_queue) + __free_dup_event(oe, event); +} + #define MAX_SAMPLE_BUFFER (64 * 1024 / sizeof(struct ordered_event)) static struct ordered_event *alloc_event(struct ordered_events *oe, union perf_event *event) @@ -100,15 +106,43 @@ static struct ordered_event *alloc_event(struct ordered_events *oe, if (!new_event) return NULL; + /* + * We maintain following scheme of buffers for ordered + * event allocation: + * + * to_free list -> buffer1 (64K) + * buffer2 (64K) + * ... + * + * Each buffer keeps an array of ordered events objects: + * buffer -> event[0] + * event[1] + * ... + * + * Each allocated ordered event is linked to one of + * following lists: + * - time ordered list 'events' + * - list of currently removed events 'cache' + * + * Allocation of the ordered event uses following order + * to get the memory: + * - use recently removed object from 'cache' list + * - use available object in current allocation buffer + * - allocate new buffer if the current buffer is full + * + * Removal of ordered event object moves it from events to + * the cache list. + */ if (!list_empty(cache)) { new = list_entry(cache->next, struct ordered_event, list); list_del(&new->list); } else if (oe->buffer) { - new = oe->buffer + oe->buffer_idx; + new = &oe->buffer->event[oe->buffer_idx]; if (++oe->buffer_idx == MAX_SAMPLE_BUFFER) oe->buffer = NULL; } else if (oe->cur_alloc_size < oe->max_alloc_size) { - size_t size = MAX_SAMPLE_BUFFER * sizeof(*new); + size_t size = sizeof(*oe->buffer) + + MAX_SAMPLE_BUFFER * sizeof(*new); oe->buffer = malloc(size); if (!oe->buffer) { @@ -122,9 +156,8 @@ static struct ordered_event *alloc_event(struct ordered_events *oe, oe->cur_alloc_size += size; list_add(&oe->buffer->list, &oe->to_free); - /* First entry is abused to maintain the to_free list. */ - oe->buffer_idx = 2; - new = oe->buffer + 1; + oe->buffer_idx = 1; + new = &oe->buffer->event[0]; } else { pr("allocation limit reached %" PRIu64 "B\n", oe->max_alloc_size); } @@ -300,15 +333,35 @@ void ordered_events__init(struct ordered_events *oe, ordered_events__deliver_t d oe->deliver = deliver; } +static void +ordered_events_buffer__free(struct ordered_events_buffer *buffer, + unsigned int max, struct ordered_events *oe) +{ + if (oe->copy_on_queue) { + unsigned int i; + + for (i = 0; i < max; i++) + __free_dup_event(oe, buffer->event[i].event); + } + + free(buffer); +} + void ordered_events__free(struct ordered_events *oe) { - while (!list_empty(&oe->to_free)) { - struct ordered_event *event; + struct ordered_events_buffer *buffer, *tmp; - event = list_entry(oe->to_free.next, struct ordered_event, list); - list_del(&event->list); - free_dup_event(oe, event->event); - free(event); + /* + * Current buffer might not have all the events allocated + * yet, we need to free only allocated ones ... + */ + list_del(&oe->buffer->list); + ordered_events_buffer__free(oe->buffer, oe->buffer_idx, oe); + + /* ... and continue with the rest */ + list_for_each_entry_safe(buffer, tmp, &oe->to_free, list) { + list_del(&buffer->list); + ordered_events_buffer__free(buffer, MAX_SAMPLE_BUFFER, oe); } } diff --git a/tools/perf/util/ordered-events.h b/tools/perf/util/ordered-events.h index 8c7a2948593e..1338d5c345dc 100644 --- a/tools/perf/util/ordered-events.h +++ b/tools/perf/util/ordered-events.h @@ -25,23 +25,28 @@ struct ordered_events; typedef int (*ordered_events__deliver_t)(struct ordered_events *oe, struct ordered_event *event); +struct ordered_events_buffer { + struct list_head list; + struct ordered_event event[0]; +}; + struct ordered_events { - u64 last_flush; - u64 next_flush; - u64 max_timestamp; - u64 max_alloc_size; - u64 cur_alloc_size; - struct list_head events; - struct list_head cache; - struct list_head to_free; - struct ordered_event *buffer; - struct ordered_event *last; - ordered_events__deliver_t deliver; - int buffer_idx; - unsigned int nr_events; - enum oe_flush last_flush_type; - u32 nr_unordered_events; - bool copy_on_queue; + u64 last_flush; + u64 next_flush; + u64 max_timestamp; + u64 max_alloc_size; + u64 cur_alloc_size; + struct list_head events; + struct list_head cache; + struct list_head to_free; + struct ordered_events_buffer *buffer; + struct ordered_event *last; + ordered_events__deliver_t deliver; + int buffer_idx; + unsigned int nr_events; + enum oe_flush last_flush_type; + u32 nr_unordered_events; + bool copy_on_queue; }; int ordered_events__queue(struct ordered_events *oe, union perf_event *event,
| |