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From: Dave Hansen <dave.hansen@intel.com>
To: Tejun Heo <tj@kernel.org>,
	Kristen Carlson Accardi <kristen@linux.intel.com>
Cc: linux-kernel@vger.kernel.org, linux-sgx@vger.kernel.org,
	cgroups@vger.kernel.org, Johannes Weiner <hannes@cmpxchg.org>,
	Michal Hocko <mhocko@kernel.org>,
	Roman Gushchin <roman.gushchin@linux.dev>,
	Shakeel Butt <shakeelb@google.com>,
	Muchun Song <songmuchun@bytedance.com>
Subject: Re: [RFC PATCH 00/20] Add Cgroup support for SGX EPC memory
Date: Thu, 22 Sep 2022 14:03:52 -0700	[thread overview]
Message-ID: <7ff6d114-a6cc-e3c5-5edb-8ac0e527d8a9@intel.com> (raw)
In-Reply-To: <YyyykUJQtYbPVctn@slm.duckdns.org>

On 9/22/22 12:08, Tejun Heo wrote:
> Can you please give more concrete examples? I'd love to hear how the SGX EPC
> memory is typically used in what amounts and what's the performance
> implications when they get reclaimed and so on. ie. Please describe a
> realistic usage scenario of contention with sufficient details on how the
> system is set up, what the applications are using the SGX EPC memory for and
> how much, how the contention on memory affects the users and so on.

One wrinkle is that the apps that use SGX EPC memory are *normal* apps.
 There are frameworks that some folks are very excited about that allow
you to run mostly unmodified app stacks inside SGX.  For example:

	https://github.com/gramineproject/graphene

In fact, Gramine users are the troublesome ones for overcommit.  Most
explicitly-written SGX applications are quite austere in their SGX
memory use; they're probably never going to see overcommit.  These
Gramine-wrapped apps are (relative) pigs.  They've been the ones finding
bugs in the existing SGX overcommit code.

So, where does all the SGX memory go?  It's the usual suspects:
memcached and redis. ;)

WARNING: multiple messages have this Message-ID (diff)
From: Dave Hansen <dave.hansen-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
To: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	Kristen Carlson Accardi
	<kristen-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-sgx-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	Johannes Weiner <hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>,
	Michal Hocko <mhocko-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	Roman Gushchin
	<roman.gushchin-fxUVXftIFDnyG1zEObXtfA@public.gmane.org>,
	Shakeel Butt <shakeelb-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>,
	Muchun Song <songmuchun-EC8Uxl6Npydl57MIdRCFDg@public.gmane.org>
Subject: Re: [RFC PATCH 00/20] Add Cgroup support for SGX EPC memory
Date: Thu, 22 Sep 2022 14:03:52 -0700	[thread overview]
Message-ID: <7ff6d114-a6cc-e3c5-5edb-8ac0e527d8a9@intel.com> (raw)
In-Reply-To: <YyyykUJQtYbPVctn-NiLfg/pYEd1N0TnZuCh8vA@public.gmane.org>

On 9/22/22 12:08, Tejun Heo wrote:
> Can you please give more concrete examples? I'd love to hear how the SGX EPC
> memory is typically used in what amounts and what's the performance
> implications when they get reclaimed and so on. ie. Please describe a
> realistic usage scenario of contention with sufficient details on how the
> system is set up, what the applications are using the SGX EPC memory for and
> how much, how the contention on memory affects the users and so on.

One wrinkle is that the apps that use SGX EPC memory are *normal* apps.
 There are frameworks that some folks are very excited about that allow
you to run mostly unmodified app stacks inside SGX.  For example:

	https://github.com/gramineproject/graphene

In fact, Gramine users are the troublesome ones for overcommit.  Most
explicitly-written SGX applications are quite austere in their SGX
memory use; they're probably never going to see overcommit.  These
Gramine-wrapped apps are (relative) pigs.  They've been the ones finding
bugs in the existing SGX overcommit code.

So, where does all the SGX memory go?  It's the usual suspects:
memcached and redis. ;)

  reply	other threads:[~2022-09-22 21:04 UTC|newest]

Thread overview: 84+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-22 17:10 [RFC PATCH 00/20] Add Cgroup support for SGX EPC memory Kristen Carlson Accardi
2022-09-22 17:10 ` [RFC PATCH 01/20] x86/sgx: Call cond_resched() at the end of sgx_reclaim_pages() Kristen Carlson Accardi
2022-09-22 17:10   ` Kristen Carlson Accardi
2022-09-23 12:32   ` Jarkko Sakkinen
2022-09-23 12:32     ` Jarkko Sakkinen
2022-09-23 12:35     ` Jarkko Sakkinen
2022-09-23 12:35       ` Jarkko Sakkinen
2022-09-23 12:37       ` Jarkko Sakkinen
2022-09-23 12:37         ` Jarkko Sakkinen
2022-09-22 17:10 ` [RFC PATCH 02/20] x86/sgx: Store EPC page owner as a 'void *' to handle multiple users Kristen Carlson Accardi
2022-09-22 17:10   ` Kristen Carlson Accardi
2022-09-22 18:54   ` Dave Hansen
2022-09-22 18:54     ` Dave Hansen
2022-09-23 12:49   ` Jarkko Sakkinen
2022-09-23 12:49     ` Jarkko Sakkinen
2022-09-22 17:10 ` [RFC PATCH 03/20] x86/sgx: Track owning enclave in VA EPC pages Kristen Carlson Accardi
2022-09-22 17:10   ` Kristen Carlson Accardi
2022-09-22 18:55   ` Dave Hansen
2022-09-22 18:55     ` Dave Hansen
2022-09-22 20:04     ` Kristen Carlson Accardi
2022-09-22 20:04       ` Kristen Carlson Accardi
2022-09-22 21:39       ` Dave Hansen
2022-09-22 21:39         ` Dave Hansen
2022-09-23 12:52   ` Jarkko Sakkinen
2022-09-23 12:52     ` Jarkko Sakkinen
2022-09-22 17:10 ` [RFC PATCH 04/20] x86/sgx: Add 'struct sgx_epc_lru' to encapsulate lru list(s) Kristen Carlson Accardi
2022-09-22 17:10   ` Kristen Carlson Accardi
2022-09-23 13:20   ` Jarkko Sakkinen
2022-09-23 13:20     ` Jarkko Sakkinen
2022-09-29 23:04     ` Kristen Carlson Accardi
2022-09-29 23:04       ` Kristen Carlson Accardi
2022-09-22 17:10 ` [RFC PATCH 05/20] x86/sgx: Introduce unreclaimable EPC page lists Kristen Carlson Accardi
2022-09-22 17:10   ` Kristen Carlson Accardi
2022-09-23 13:29   ` Jarkko Sakkinen
2022-09-23 13:29     ` Jarkko Sakkinen
2022-09-22 17:10 ` [RFC PATCH 06/20] x86/sgx: Introduce RECLAIM_IN_PROGRESS flag for EPC pages Kristen Carlson Accardi
2022-09-22 17:10   ` Kristen Carlson Accardi
2022-09-22 17:10 ` [RFC PATCH 07/20] x86/sgx: Use a list to track to-be-reclaimed pages during reclaim Kristen Carlson Accardi
2022-09-22 17:10   ` Kristen Carlson Accardi
2022-09-22 17:10 ` [RFC PATCH 08/20] x86/sgx: Add EPC page flags to identify type of page Kristen Carlson Accardi
2022-09-22 17:10   ` Kristen Carlson Accardi
2022-09-22 17:10 ` [RFC PATCH 09/20] x86/sgx: Allow reclaiming up to 32 pages, but scan 16 by default Kristen Carlson Accardi
2022-09-22 17:10   ` Kristen Carlson Accardi
2022-09-22 17:10 ` [RFC PATCH 10/20] x86/sgx: Return the number of EPC pages that were successfully reclaimed Kristen Carlson Accardi
2022-09-22 17:10   ` Kristen Carlson Accardi
2022-09-22 17:10 ` [RFC PATCH 11/20] x86/sgx: Add option to ignore age of page during EPC reclaim Kristen Carlson Accardi
2022-09-22 17:10   ` Kristen Carlson Accardi
2022-09-22 17:10 ` [RFC PATCH 12/20] x86/sgx: Add helper to retrieve SGX EPC LRU given an EPC page Kristen Carlson Accardi
2022-09-22 17:10   ` Kristen Carlson Accardi
2022-09-22 17:10 ` [RFC PATCH 13/20] x86/sgx: Prepare for multiple LRUs Kristen Carlson Accardi
2022-09-22 17:10   ` Kristen Carlson Accardi
2022-09-22 17:10 ` [RFC PATCH 14/20] x86/sgx: Expose sgx_reclaim_pages() for use by EPC cgroup Kristen Carlson Accardi
2022-09-22 17:10   ` Kristen Carlson Accardi
2022-09-22 17:10 ` [RFC PATCH 15/20] x86/sgx: Add helper to grab pages from an arbitrary EPC LRU Kristen Carlson Accardi
2022-09-22 17:10   ` Kristen Carlson Accardi
2022-09-22 17:10 ` [RFC PATCH 16/20] x86/sgx: Add EPC OOM path to forcefully reclaim EPC Kristen Carlson Accardi
2022-09-22 17:10   ` Kristen Carlson Accardi
2022-09-22 17:10 ` [RFC PATCH 17/20] cgroup, x86/sgx: Add SGX EPC cgroup controller Kristen Carlson Accardi
2022-09-22 17:10   ` Kristen Carlson Accardi
2022-09-22 17:10 ` [RFC PATCH 18/20] x86/sgx: Enable EPC cgroup controller in SGX core Kristen Carlson Accardi
2022-09-22 17:10   ` Kristen Carlson Accardi
2022-09-22 17:10 ` [RFC PATCH 19/20] x86/sgx: Add stats and events interfaces to EPC cgroup controller Kristen Carlson Accardi
2022-09-22 17:10   ` Kristen Carlson Accardi
2022-09-22 17:10 ` [RFC PATCH 20/20] docs, cgroup, x86/sgx: Add SGX EPC cgroup controller documentation Kristen Carlson Accardi
2022-09-22 17:41 ` [RFC PATCH 00/20] Add Cgroup support for SGX EPC memory Tejun Heo
2022-09-22 17:41   ` Tejun Heo
2022-09-22 18:59   ` Kristen Carlson Accardi
2022-09-22 18:59     ` Kristen Carlson Accardi
2022-09-22 19:08     ` Tejun Heo
2022-09-22 19:08       ` Tejun Heo
2022-09-22 21:03       ` Dave Hansen [this message]
2022-09-22 21:03         ` Dave Hansen
2022-09-24  0:09         ` Tejun Heo
2022-09-24  0:09           ` Tejun Heo
2022-09-26 18:30           ` Kristen Carlson Accardi
2022-09-26 18:30             ` Kristen Carlson Accardi
2022-10-07 16:39           ` Kristen Carlson Accardi
2022-10-07 16:39             ` Kristen Carlson Accardi
2022-10-07 16:42             ` Tejun Heo
2022-10-07 16:42               ` Tejun Heo
2022-10-07 16:46               ` Kristen Carlson Accardi
2022-10-07 16:46                 ` Kristen Carlson Accardi
2022-09-23 12:24 ` Jarkko Sakkinen
2022-09-23 12:24   ` Jarkko Sakkinen

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