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Re: [Qemu-devel] [PATCH 04/15] coroutine: add a knob to disable the shar
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH 04/15] coroutine: add a knob to disable the shared release pool |
Date: |
Tue, 28 Jun 2016 12:41:06 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.1.1 |
On 28/06/2016 11:01, Peter Lieven wrote:
> the current coroutine freelist implementation has 2 kinds of pools.
> One shared release pool between all threads and additionally one
> allocation pool per thread. The release pool is especially necessary
> if the coroutine is created in a different thread than it is released.
> This is e.g. the case if an IDE interface is used.
>
> But in times of virtio and dataplane the the release pool adds costs
> which are not entirely necessary. At first if virtio is used the release
> pool tends to fill up to 100% because all coroutines are first handed
> back to the release pool. On coroutine create a thread can steal this
> release pool and make it its local allocation pool, but during mixed
> I/O pattern at the end the release pool is full of useless coroutines
> and the alloc_pool has also filled to maximum size.
The cost is 2^16 bytes * 2^6 coroutines, that is 4 MB. I don't think
this is worth an extra knob that no one will use...
Paolo
- Re: [Qemu-devel] [PATCH 09/15] loader: use mmap for ROMs, (continued)
Re: [Qemu-devel] [PATCH 07/15] qapi: use mmap for QmpInputVisitor, Paolo Bonzini, 2016/06/28
[Qemu-devel] [PATCH 10/15] vmware_svga: use mmap for scratch pad, Peter Lieven, 2016/06/28
[Qemu-devel] [PATCH 04/15] coroutine: add a knob to disable the shared release pool, Peter Lieven, 2016/06/28
- Re: [Qemu-devel] [PATCH 04/15] coroutine: add a knob to disable the shared release pool,
Paolo Bonzini <=
[Qemu-devel] [PATCH 05/15] util: add a helper to mmap private anonymous memory, Peter Lieven, 2016/06/28
[Qemu-devel] [PATCH 06/15] exec: use mmap for subpages, Peter Lieven, 2016/06/28
Re: [Qemu-devel] [PATCH 00/15] optimize Qemu RSS usage, Paolo Bonzini, 2016/06/28