X-Recipient: archive-cygwin AT delorie DOT com DomainKey-Signature: a=rsa-sha1; c=nofws; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:date:from:to:subject:message-id:reply-to :references:mime-version:content-type:in-reply-to; q=dns; s= default; b=D0mmAwEnl4ijmzlanjXXGR4le7gqsCqqISgwP3yEp99W5Abc8fsO9 gKpsBDPTnCJTUHYVuaSV0CMMhZEbgW5N5zPkyYmVry7KGawqcr81YBPY6uR6EgUy tFUDrK5SoXf6VAW7bBq3MD3DtbVfonYAuNEJgwVz0mMShdrNNDdEaI= DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:date:from:to:subject:message-id:reply-to :references:mime-version:content-type:in-reply-to; s=default; bh=O0x8R22vHS6rOd6SIxsnMoBHCP8=; b=fx2EzEUcN+se98uNxoU/js0DHrNv 5lm41UtAGVH3NxUVjbM/UYpaRXGHpAPfrvcOpzOkTeWDop26d3iuB+RKNIcoCZ7n JoU3+NR9BjLfM7+DyS1E40BoJ/jCuPFFj2yZchQYpqybwUVX35rRxMrKf782oNw/ inaM1tohKYCJMF0= Mailing-List: contact cygwin-help AT cygwin DOT com; run by ezmlm List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: cygwin-owner AT cygwin DOT com Mail-Followup-To: cygwin AT cygwin DOT com Delivered-To: mailing list cygwin AT cygwin DOT com Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-103.9 required=5.0 tests=AWL,BAYES_00,GOOD_FROM_CORINNA_CYGWIN,RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 spammy=HX-Languages-Length:1274 X-HELO: mout.kundenserver.de Date: Wed, 7 Aug 2019 10:20:10 +0200 From: Corinna Vinschen To: cygwin AT cygwin DOT com Subject: Re: semget() returns EAGAIN? Message-ID: <20190807082010.GZ11632@calimero.vinschen.de> Reply-To: cygwin AT cygwin DOT com Mail-Followup-To: cygwin AT cygwin DOT com References: <20190807081242 DOT GY11632 AT calimero DOT vinschen DOT de> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="rdeY6f/ml8+xnc5C" Content-Disposition: inline In-Reply-To: <20190807081242.GY11632@calimero.vinschen.de> User-Agent: Mutt/1.11.3 (2019-02-01) --rdeY6f/ml8+xnc5C Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Aug 7 10:12, Corinna Vinschen wrote: > On Aug 7 05:02, Lavrentiev, Anton (NIH/NLM/NCBI) [C] via cygwin wrote: > > I'm noticing that in a high-contention situation (many processes try > > to get ahold of a semaphore) semget() on Cygwin starts to return > > EAGAIN (try again) after about 62 processes has gotten to call > > semget() and are actively competing for the semaphore (i.e. using the > > semaphore ID semget() returned to them). > >=20 > > EAGAIN is not documented in any of semget() API documentation that I > > can find. > >=20 > > I understand that in Cygwin semget() is implemented as a connection to > > cygserver, and the error probably stems from there, but I don't think > > that such a code is appropriate as a final errno. And why is there a > > limit, to begin with? What exactly imposes it? >=20 > The number of parallel open pipes, for instance. By default, 10 > worker threads handle the load and up to 62 processes can be handled > in parallel. If the numbers are too low in your scenario, try to > raise them in /etc/cygserver.conf. Apart from that, the preferred way to use semaphores is to use POSIX semaphores, that is, sem_open and friends. These don't require cygserver. Corinna --=20 Corinna Vinschen Cygwin Maintainer --rdeY6f/ml8+xnc5C Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEoVYPmneWZnwT6kwF9TYGna5ET6AFAl1KiboACgkQ9TYGna5E T6DeqA/5AbzAwaJOSSu/CjYcPFa1lTpEIoNYc5BYZj3lBoECwii0qM1SJwDeOk5G xTihhsfIH+Qa1/7y3qsEJp/2CHp5MtZSzz2ITVK4CE3AkiHhe/s7stNUKekshOlI l1SdqlQJfhqLuovqpXHjmajkPArH5Zf8zxxh07zltL116Bod1Fs+PnnOJesd0gSt Ga/nov8ooWFQyMM7LnUUYxbdBbojbSszxHAhMTw/ZGCVcW3zKDlUnLMHVCKFE27+ OfyKtuYz7UFLyr/MxVJhxaVxWU9IGILsFiR8t1CUn7PuKcGYmvEgthBXZzp89E/+ 7JaJ2hcv2Yqtg4irmzVjQ6i4k2abuOymB9JCpvMtyeoosgG7HvlJRlHnWa6e/4nx /vXYJZRFQkACdB2xN34dGcuee0DksS8renrYrxqOt9V/HmbkZZDl+hteFp6keKHA wCLAfJ/fTTG2v/9kcWQiIgu8+JuouYBT789+u7KdsF13IKVnIP2NE7/QMljvXjsV +JdIQ/Fxs95yghqQB2thakIj0KeX4/G04z2jlhEd3lSUwHB9YZAmnzG0vioAzaIK QNIq84P3oqek31hnpEO8CxjHHIqnx9SCaOQ97omwy/E7jpdGQxdm/z6WVOBqSiRY v3u0CZh8Oa1T+HcCbDncrY5fL44GzgjJkJXKWs6vVo0+2WrFIQw= =q/4t -----END PGP SIGNATURE----- --rdeY6f/ml8+xnc5C--