Re: Patch: Improve HTTP time by sending Connection:close

[Daniel Kiper]

On Sat, Nov 12, 2016 at 09:26:17AM -0800, Walter Huf wrote:
> GRUB's HTTP module declares support for HTTP/1.1, which defaults to
> Connection:keepalive. At the end of the content, the server holds the TCP
> connection open waiting for the next request.
> It seems that grub_net_poll_cards() is watching for the HTTP module to set

Do you have a feeling or are you sure? I think that we have to be sure here.

> net->stall, and otherwise waits the full 400ms GRUB_NET_INTERVAL to return
> to processing. However, HTTP module only sets that flag in specific
> conditions:
>
>    - parse_line detects that we are at the end of downloading a chunked
>    Transfer-Encoding
>    - http_err detects a problem with the underlying TCP connection
>    - http_receive has queued 20 netbuffer packets for processing
>
> If the file is small and takes less than 20 packets, and the server is not
> using chunked encoding, grub_net_poll_cards() will wait the full 400ms
> before continuing to process and finish the file download.
>
> This patch sets Connection:close, which will tell the server to close the
> connection as soon as it has finished sending the file. GRUB closes any
> connections that are left open (in http_seek), so it does not change

Why in http_seek? Is it correct or not?

> performance. When the server disconnects, I think it triggers http_err and

"I think" is too soft. You have to be sure here.

> then quits out of grub_net_poll_cards early.

Lack of SOB.

Have you tested this patch with large/huge number of files to transfer? I have
a feeling that it can slowdown whole transfer in such cases due to number of
connects/disconnects. Maybe this feature should be conditional thing.

Daniel