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From: Stefan Reiter <s.reiter@proxmox.com>
To: Dietmar Maurer <dietmar@proxmox.com>,
	Proxmox Backup Server development discussion
	<pbs-devel@lists.proxmox.com>
Subject: Re: [pbs-devel] [PATCH proxmox-backup 2/3] RemoteChunkReader: add LRU cached variant
Date: Thu, 29 Apr 2021 10:06:55 +0200	[thread overview]
Message-ID: <a2cb6f41-0d90-a3bf-1b4e-d55dd1b3b5d7@proxmox.com> (raw)
In-Reply-To: <1849352005.1381.1619627181675@webmail.proxmox.com>

On 28/04/2021 18:26, Dietmar Maurer wrote:
> 
>> +    /// Create a new instance.
>> +    ///
>> +    /// Chunks listed in ``cache_hint`` are cached and kept in RAM, as well as the last
>> +    /// 'cache_lru' accessed chunks (the latter via a mmap file).
> 
> Does that cache_hint really helps here?
> Have you tested without? If so, whats the difference?
> 

Again, performance testing is hard with this (I'll take a closer look at 
why as well), but in terms of hit rate the "hinted" cache is at about 
1-2% - we could probably reduce it's size.

Removing it entirely would probably not be good, as I think we use it to 
cache the zero-chunk as well IIRC?




  reply	other threads:[~2021-04-29  8:06 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-28 16:26 Dietmar Maurer
2021-04-29  8:06 ` Stefan Reiter [this message]
  -- strict thread matches above, loose matches on Subject: below --
2021-04-29  8:12 Dietmar Maurer
2021-04-28 16:06 [pbs-devel] [PATCH 0/3] Add cache for live-restore Stefan Reiter
2021-04-28 16:06 ` [pbs-devel] [PATCH proxmox-backup 2/3] RemoteChunkReader: add LRU cached variant Stefan Reiter

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