From: Sebastian Gniazdowski <sgniazdowski@gmail.com>
To: zsh-workers@zsh.org
Subject: Re: Slowdown around 5.0.5-dev-0
Date: Fri, 23 Oct 2015 17:40:09 +0200 [thread overview]
Message-ID: <CAKc7PVDNkhv351ctq1f60WsbTspR-UA8rzW0vfCdEx2iM3mxYA@mail.gmail.com> (raw)
In-Reply-To: <151022080024.ZM6471@torch.brasslantern.com>
[-- Attachment #1: Type: text/plain, Size: 1050 bytes --]
I attach the patch that withdraws 9f8e3e8 and 643aca9 (which are 36834)
Best regards,
Sebastian Gniazdowski
On 22 October 2015 at 17:00, Bart Schaefer <schaefer@brasslantern.com> wrote:
> On Oct 22, 2:49pm, Sebastian Gniazdowski wrote:
> }
> } My conclusions:
> } - 36834 introduces high memory usage; I would suggest to use only two
> } optimizations -- newheaps and zhalloc; my znavtools are instant fast
> } with them, what's slower is searching (wrote search_test function,
> } results attached)
>
> My apologies, but I'm not sure I followed all of that. Can you produce
> a diff against commit 8e9a68ad14655c1949b1a04d5715a5caa8c344ee that
> shows the situation you think is the best so far?
>
> } - still not sure why 36834 allocates much memory for the string test
>
> Seeing the aforementioned diff may provide a hint.
>
> } - newheaps makes function calls longer, but it's not a substantial
> } difference
>
> 14% is pretty substantial, but it's probably all gained back if the
> function does anything significant with local variables.
[-- Attachment #2: fheaps_revert.patch --]
[-- Type: application/octet-stream, Size: 4413 bytes --]
diff --git a/Src/mem.c b/Src/mem.c
index 68bd767..63a5afe 100644
--- a/Src/mem.c
+++ b/Src/mem.c
@@ -294,7 +294,7 @@ pushheap(void)
#endif
for (h = heaps; h; h = h->next) {
- DPUTS(!h->used && h->next, "BUG: empty heap");
+ DPUTS(!h->used, "BUG: empty heap");
hs = (Heapstack) zalloc(sizeof(*hs));
hs->next = h->sp;
h->sp = hs;
@@ -334,15 +334,17 @@ freeheap(void)
*
* Whenever fheap is NULL here, the loop below sweeps back over the
* entire heap list again, resetting the free space in every arena to
- * the amount stashed by pushheap() and finding the arena with the most
+ * the amount stashed by pushheap() and finding the first arena with
* free space to optimize zhalloc()'s next search. When there's a lot
* of stuff already on the heap, this is an enormous amount of work,
* and performance goes to hell.
*
- * Therefore, we defer freeing the most recently allocated arena until
- * we reach popheap(). This may fail to reclaim some space in earlier
- * arenas.
- *
+ * However, if the arena to which fheap points is unused, we want to
+ * free it, so we have no choice but to do the sweep for a new fheap.
+ */
+ if (fheap && !fheap->sp)
+ fheap = NULL; /* We used to do this unconditionally */
+ /*
* In other cases, either fheap is already correct, or it has never
* been set and this loop will do it, or it'll be reset from scratch
* on the next popheap(). So all that's needed here is to pick up
@@ -359,11 +361,7 @@ freeheap(void)
memset(arena(h) + h->sp->used, 0xff, h->used - h->sp->used);
#endif
h->used = h->sp->used;
- if (!fheap) {
- if (h->used < ARENA_SIZEOF(h))
- fheap = h;
- } else if (ARENA_SIZEOF(h) - h->used >
- ARENA_SIZEOF(fheap) - fheap->used)
+ if (!fheap && h->used < ARENA_SIZEOF(h))
fheap = h;
hl = h;
#ifdef ZSH_HEAP_DEBUG
@@ -386,26 +384,6 @@ freeheap(void)
VALGRIND_MEMPOOL_TRIM((char *)h, (char *)arena(h), h->used);
#endif
} else {
- if (fheap == h)
- fheap = NULL;
- if (h->next) {
- /* We want to cut this out of the arena list if we can */
- if (h == heaps)
- hl = heaps = h->next;
- else if (hl && hl->next == h)
- hl->next = h->next;
- else {
- DPUTS(hl, "hl->next != h when freeing");
- hl = h;
- continue;
- }
- h->next = NULL;
- } else {
- /* Leave an empty arena at the end until popped */
- h->used = 0;
- fheap = hl = h;
- break;
- }
#ifdef USE_MMAP
munmap((void *) h, h->size);
#else
@@ -463,29 +441,12 @@ popheap(void)
#ifdef ZSH_VALGRIND
VALGRIND_MEMPOOL_TRIM((char *)h, (char *)arena(h), h->used);
#endif
- if (!fheap) {
- if (h->used < ARENA_SIZEOF(h))
- fheap = h;
- } else if (ARENA_SIZEOF(h) - h->used >
- ARENA_SIZEOF(fheap) - fheap->used)
+ if (!fheap && h->used < ARENA_SIZEOF(h))
fheap = h;
zfree(hs, sizeof(*hs));
hl = h;
} else {
- if (h->next) {
- /* We want to cut this out of the arena list if we can */
- if (h == heaps)
- hl = heaps = h->next;
- else if (hl && hl->next == h)
- hl->next = h->next;
- else {
- DPUTS(hl, "hl->next != h when popping");
- hl = h;
- continue;
- }
- h->next = NULL;
- }
#ifdef USE_MMAP
munmap((void *) h, h->size);
#else
@@ -563,7 +524,7 @@ zheapptr(void *p)
mod_export void *
zhalloc(size_t size)
{
- Heap h, hp = NULL;
+ Heap h;
size_t n;
#ifdef ZSH_VALGRIND
size_t req_size = size;
@@ -590,7 +551,6 @@ zhalloc(size_t size)
* so why start over at heaps just because fheap has too little?
*/
for (h = (fheap ? fheap : heaps); h; h = h->next) {
- hp = h;
if (ARENA_SIZEOF(h) >= (n = size + h->used)) {
void *ret;
@@ -611,6 +571,7 @@ zhalloc(size_t size)
}
}
{
+ Heap hp;
/* not found, allocate new heap */
#if defined(ZSH_MEM) && !defined(USE_MMAP)
static int called = 0;
@@ -619,6 +580,7 @@ zhalloc(size_t size)
#endif
n = HEAP_ARENA_SIZE > size ? HEAPSIZE : size + sizeof(*h);
+ for (hp = NULL, h = heaps; h; hp = h, h = h->next);
#ifdef USE_MMAP
h = mmap_heap_alloc(&n);
@@ -650,7 +612,6 @@ zhalloc(size_t size)
VALGRIND_MEMPOOL_ALLOC((char *)h, (char *)arena(h), req_size);
#endif
- DPUTS(hp && hp->next, "failed to find end of chain in zhalloc");
if (hp)
hp->next = h;
else
next prev parent reply other threads:[~2015-10-23 15:40 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-10 10:54 Sebastian Gniazdowski
2015-10-10 17:58 ` Bart Schaefer
2015-10-10 18:11 ` Sebastian Gniazdowski
2015-10-10 18:32 ` Sebastian Gniazdowski
2015-10-11 0:06 ` Bart Schaefer
2015-10-11 6:20 ` Bart Schaefer
2015-10-11 8:39 ` Sebastian Gniazdowski
2015-10-11 16:17 ` Bart Schaefer
2015-10-11 16:48 ` Sebastian Gniazdowski
2015-10-11 17:31 ` Bart Schaefer
2015-10-11 18:05 ` Sebastian Gniazdowski
2015-10-11 21:22 ` Bart Schaefer
2015-10-12 8:21 ` Sebastian Gniazdowski
2015-10-12 14:01 ` Bart Schaefer
2015-10-12 16:50 ` Sebastian Gniazdowski
2015-10-13 0:33 ` Bart Schaefer
2015-10-13 8:21 ` Sebastian Gniazdowski
2015-10-13 15:52 ` Bart Schaefer
2015-10-14 6:50 ` Sebastian Gniazdowski
2015-10-14 13:27 ` Peter Stephenson
2015-10-14 16:25 ` Bart Schaefer
2015-10-14 16:50 ` Bart Schaefer
2015-10-15 4:32 ` Bart Schaefer
2015-10-15 13:03 ` Sebastian Gniazdowski
2015-10-16 0:35 ` Bart Schaefer
2015-10-17 9:12 ` Sebastian Gniazdowski
2015-10-17 9:24 ` Sebastian Gniazdowski
2015-10-18 16:19 ` Bart Schaefer
2015-10-18 20:40 ` Sebastian Gniazdowski
2015-10-18 21:07 ` Bart Schaefer
2015-10-18 21:31 ` Sebastian Gniazdowski
2015-10-19 17:21 ` Bart Schaefer
2015-10-22 12:49 ` Sebastian Gniazdowski
2015-10-22 15:00 ` Bart Schaefer
2015-10-22 16:28 ` Sebastian Gniazdowski
2015-10-22 16:33 ` Sebastian Gniazdowski
2015-10-23 15:40 ` Sebastian Gniazdowski [this message]
2015-10-23 15:57 ` Sebastian Gniazdowski
2015-10-23 19:26 ` Bart Schaefer
2015-10-23 23:50 ` Bart Schaefer
2015-10-24 6:09 ` Sebastian Gniazdowski
2015-10-24 7:37 ` Sebastian Gniazdowski
2015-10-24 8:04 ` Sebastian Gniazdowski
2015-10-24 19:39 ` Bart Schaefer
2015-10-25 7:35 ` Sebastian Gniazdowski
2015-10-25 17:23 ` Bart Schaefer
2015-10-25 20:56 ` Sebastian Gniazdowski
2015-10-26 0:49 ` Bart Schaefer
2015-10-26 7:41 ` Sebastian Gniazdowski
2015-10-26 7:47 ` Sebastian Gniazdowski
2015-10-24 6:27 ` Sebastian Gniazdowski
2015-10-24 10:54 ` Sebastian Gniazdowski
2015-10-24 11:25 ` Sebastian Gniazdowski
2015-10-24 16:31 ` Bart Schaefer
2015-10-24 16:41 ` Bart Schaefer
2015-10-23 6:32 ` Sebastian Gniazdowski
2015-10-16 0:37 ` Bart Schaefer
2015-10-13 13:07 ` Sebastian Gniazdowski
2015-10-13 13:31 ` Sebastian Gniazdowski
2015-10-12 12:05 ` Sebastian Gniazdowski
2015-10-12 15:13 ` Bart Schaefer
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