The HTTP layer used to make a copy of each incoming header and its
value for a request. Stop doing that and make HTTP headers zero-copy
all across the board.
This change comes with some api function changes, notably the
http_request_header() function which now takes a const char ** rather
than a char ** out pointer.
This commit also constifies several members of http_request, beware.
Additional rework how the worker processes deal with the accept lock.
Before:
if a worker held the accept lock and it accepted a new connection
it would release the lock for others and back off for 500ms before
attempting to grab the lock again.
This approach worked but under high load this starts becoming obvious.
Now:
- workers not holding the accept lock and not having any connections
will wait less long before returning from kore_platform_event_wait().
- workers not holding the accept lock will no longer blindly wait
an arbitrary amount in kore_platform_event_wait() but will look
at how long until the next lock grab is and base their timeout
on that.
- if a worker its next_lock timeout is up and failed to grab the
lock it will try again in half the time again.
- the worker process holding the lock will when releasing the lock
double check if it still has space for newer connections, if it does
it will keep the lock until it is full. This prevents the lock from
bouncing between several non busy worker processes all the time.
Additional fixes:
- Reduce the number of times we check the timeout list, only do it twice
per second rather then every event tick.
- Fix solo worker count for TLS (we actually hold two processes, not one).
- Make sure we don't accidentally miscalculate the idle time causing new
connections under heavy load to instantly drop.
- Swap from gettimeofday() to clock_gettime() now that MacOS caught up.
- Change pools to use mmap() for allocating regions.
- Change kore_malloc() to use pools for commonly sized objects.
(split into multiple of 2 buckets, starting at 8 bytes up to 8192).
- Rename kore_mem_free() to kore_free().
The preallocated pools will hold up to 128K of elements per block size.
In case a larger object is to be allocated kore_malloc() will use
malloc() instead.
kore_buf_create and kore_buf_free do use kore_malloc. But sometimes you
may embed a kore_buf inside a structure and would like a single way to
initialize / destroy it.
Change the callback prototypes to:
void callback(struct kore_msg *msg, const void *data);
This allows the callbacks to receive the full kore_msg data structure
as sent over the wire (including length and id). Useful for future
additions to the kore_msg structure (such as worker origin).
Several other improvements:
* Accesslog now uses the msg framework as well.
* Websocket WEBSOCKET_BROADCAST_GLOBAL now works.
Small websocket improvement in this commit:
* Build the frame to be sent only once when broadcasting
instead of per connection we are broadcasting towards.
kore_buf_replace_string allows you to replace occurances of a certain
string with something else.
Example:
char *username = "Joris";
page = kore_buf_create(static_len_html_profile);
kore_buf_append(page, static_html_profile, static_len_html_profile);
kore_buf_replace_string(page, "%name%", username, strlen(username));
- Introduce own memory management system on top of malloc to keep track
of all our allocations and free's. Later we should introduce a pooling
mechanism for fixed size allocations (http_request comes to mind).
- Introduce ssl_cipher in configuration.
Memory usage is kind of high right now, but it seems its OpenSSL
doing it rather then Kore.
Joris Vink
Raphaël Monrouzeau
Stig Telfer
Carl Ekerot
PauloMelo