On Tue, Nov 15, 2016 at 4:21 PM, Daniel Kiper <dki...@net-space.pl> wrote: > 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. >
See http://savannah.gnu.org/bugs/?49531 which has more details. >> 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. > I must have missed it. Is it now required? > 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. > Currently grub will always establish new connection in http_open -> http_establish, so it should not change anything from grub PoV, but reduce amount of lingering connections on server. But I would really like to explore another patch in above bug report - gracefully close connection when we finished receive data. That said, this one does not hurt as long as we do not reuse existing connection. _______________________________________________ Grub-devel mailing list Grub-devel@gnu.org https://lists.gnu.org/mailman/listinfo/grub-devel
