king: pre-allocate buffer in king_curl_bytes if possible#1000
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A user observed that downloading the initial pill on windows was taking forever, so I started my investigation. The debugger showed me that no matter when I paused execution I was always ending up on c3_realloc in king_curl_alloc. It turns out that realloc is dog slow on windows because it doesn't have anything like mremap. Here we change the memory allocation strategy in king_curl_bytes to the following: 1. If we get a Content-Length header, we parse that and pre-allocate. 2. If we don't or the header is lying, we amortize the reallocs by always doubling the capacity of the buffer when it runs out.
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A user observed that downloading the initial pill on windows was taking forever, so I started my investigation. No matter when I paused execution in the debugger I was always ending up on
c3_reallocinking_curl_alloc. It turns out thatreallocis dog slow on windows because it doesn't have anything likemremap.Here we change the memory allocation strategy in king_curl_bytes to the following:
If we get a Content-Length header, we parse that and pre-allocate.
If we don't or the header is lying, we amortize the reallocs by always doubling the capacity of the buffer when it runs out.