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From: David Turner <novalis@novalis.org>
To: Eric Wong <e@80x24.org>
Cc: Duy Nguyen <pclouds@gmail.com>, kamggg@gmail.com, git@vger.kernel.org
Subject: Re: [PATCH v12 04/20] index-helper: new daemon for caching index and related stuff
Date: Sun, 26 Jun 2016 13:49:57 -0400	[thread overview]
Message-ID: <577015C5.8070407@novalis.org> (raw)
In-Reply-To: <20160626085347.GA4053@dcvr.yhbt.net>

On 06/26/2016 04:53 AM, Eric Wong wrote:
> David Turner <novalis@novalis.org> wrote:
>> On 06/25/2016 10:33 AM, Duy Nguyen wrote:
>>>> +               /*
>>>> +                * Our connection to the client is blocking since a client
>>>> +                * can always be killed by SIGINT or similar.
>>>> +                */
>>>> +               set_socket_blocking_flag(client_fd, 0);
>>>
>>> Out of curiosity, do we really need this? I thought default behavior
>>> was always blocking (and checked linux kernel, it seemed to agree with
>>> me). Maybe for extra safety because other OSes may default to
>>> something else?
>>
>> Yes -- see this bug report for details:
>> https://bugs.python.org/issue7995
>
> I realize it's an issue with BSDs, but it still seems
> unnecessary, here:
>
> 1) the packet_read => get_packet_data => read_in_full => xread
>     call chain already poll()s on EAGAIN/EWOULDBLOCK.
>     write_in_full => xwrite busy loops on EAGAIN/EWOULDBLOCK.
>     xwrite should probably poll, too; but I guess EAGAIN is
>     uncommon with small writes.

That is a CPU-burning busy loop on a non-blocking socket.

> 2) you create the listen fd you call accept on and never set
>     non-blocking on it.  It might be an issue one day if
>     we use socket activation and inherit a socket, but the
>     retries mentioned in 1) should cover that case.

Hm.  I wonder why I thought I had made it non-blocking.

I'm sort of reluctant to change this as I no longer have a Mac to test 
on.  Does someone else have a Mac that they can use to test this?


  reply	other threads:[~2016-06-26 17:50 UTC|newest]

Thread overview: 49+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-05-19 21:45 [PATCH v12 00/20] index-helper/watchman David Turner
2016-05-19 21:45 ` [PATCH v12 01/20] read-cache.c: fix constness of verify_hdr() David Turner
2016-05-19 21:45 ` [PATCH v12 02/20] read-cache: allow to keep mmap'd memory after reading David Turner
2016-05-19 21:45 ` [PATCH v12 03/20] pkt-line: add gentle version of packet_write David Turner
2016-06-25 14:01   ` Duy Nguyen
2016-05-19 21:45 ` [PATCH v12 04/20] index-helper: new daemon for caching index and related stuff David Turner
2016-06-17 16:43   ` Christian Couder
2016-06-25 14:15     ` Duy Nguyen
2016-06-25 14:33   ` Duy Nguyen
2016-06-25 19:21     ` David Turner
2016-06-26  4:27       ` Duy Nguyen
2016-06-26 19:29         ` David Turner
2016-06-27  5:50           ` Duy Nguyen
2016-06-26  8:53       ` Eric Wong
2016-06-26 17:49         ` David Turner [this message]
2016-06-26 23:25           ` Eric Wong
2016-05-19 21:45 ` [PATCH v12 05/20] index-helper: add --strict David Turner
2016-06-25 14:43   ` Duy Nguyen
2016-05-19 21:45 ` [PATCH v12 06/20] daemonize(): set a flag before exiting the main process David Turner
2016-05-19 21:45 ` [PATCH v12 07/20] index-helper: add --detach David Turner
2016-06-25 14:46   ` Duy Nguyen
2016-05-19 21:45 ` [PATCH v12 08/20] index-helper: log warnings David Turner
2016-05-19 21:45 ` [PATCH v12 09/20] read-cache: add watchman 'WAMA' extension David Turner
2016-06-25 14:59   ` Duy Nguyen
2016-05-19 21:45 ` [PATCH v12 10/20] watchman: support watchman to reduce index refresh cost David Turner
2016-06-17 16:01   ` Christian Couder
2016-05-19 21:45 ` [PATCH v12 11/20] index-helper: use watchman to avoid refreshing index with lstat() David Turner
2016-06-17 13:02   ` Duy Nguyen
2016-06-17 21:39     ` David Turner
2016-06-19  5:07     ` [PATCH v12 11/20] index-helper: use watchman to avoid refreshing, " David Turner
2016-06-23  6:24       ` David Turner
2016-06-23 15:33         ` Duy Nguyen
2016-06-25 16:27   ` [PATCH v12 11/20] index-helper: use watchman to avoid refreshing " Duy Nguyen
2016-05-19 21:45 ` [PATCH v12 12/20] update-index: enable/disable watchman support David Turner
2016-06-25 16:31   ` Duy Nguyen
2016-05-19 21:45 ` [PATCH v12 13/20] unpack-trees: preserve index extensions David Turner
2016-05-19 21:45 ` [PATCH v12 14/20] watchman: add a config option to enable the extension David Turner
2016-05-19 21:45 ` [PATCH v12 15/20] index-helper: kill mode David Turner
2016-05-19 21:45 ` [PATCH v12 16/20] index-helper: don't run if already running David Turner
2016-06-17 16:18   ` Christian Couder
2016-05-19 21:45 ` [PATCH v12 17/20] index-helper: autorun mode David Turner
2016-06-25 16:35   ` Duy Nguyen
2016-05-19 21:45 ` [PATCH v12 18/20] index-helper: optionally automatically run David Turner
2016-06-25 16:38   ` Duy Nguyen
2016-05-19 21:45 ` [PATCH v12 19/20] trace: measure where the time is spent in the index-heavy operations David Turner
2016-05-19 21:45 ` [PATCH v12 20/20] index-helper: indexhelper.exitafter config David Turner
2016-06-25 13:28 ` [PATCH v12 00/20] index-helper/watchman Duy Nguyen
2016-06-25 16:42   ` Duy Nguyen
2016-06-26  4:08   ` David Turner

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