Reduce max bucket size
Turns out that we were spending a lot of time initializing
buckets. Reducing the size of the bucket reduces max alloc
latency significantly, since we're not spending tens of
milliseconds initializing hundreds of thousands of slots.
@@ -30,7 +30,7 @@ pkg std =
const Zslab = (0 : slab#)
const Zchunk = (0 : chunk#)
-const Slabsz = 4*MiB
+const Slabsz = 512*KiB
const Cachemax = 4
const Bktmax = 128*KiB /* a balance between wasted space and falling back to mmap */
const Pagesz = 4*KiB
