Re: patch to commit soon: PR25375 debuginfod prefetching

[Mark Wielaard <mark at klomp dot org>]

Hi Frank,

On Mon, 2020-02-24 at 17:29 -0500, Frank Ch. Eigler wrote:
> This patch has been baking on my public servers awhile and can make a
> huge difference in performance.  It's not something immediately
> obvious how or whether to test, as it's a pure performance improvement.
> Planning to push shortly.

As far as I understand it, it looks good.
One tiny question:

> @@ -2809,7 +2857,8 @@ main (int argc, char *argv[])
>      fdcache_mbs = 1024; // 1 gigabyte
>    else
>      fdcache_mbs = sfs.f_bavail * sfs.f_bsize / 1024 / 1024 / 4; // 25% of free space
> -  fdcache_fds = concurrency * 2;
> +  fdcache_prefetch = 64; // guesstimate storage is this much less costly than re-decompression
> +  fdcache_fds = (concurrency + fdcache_prefetch) * 2;

Here fdcache_prefetch is set and used before argp_parse () is called,
which would set it to the user supplied value (if any). Is that
intentional?

Cheers,

Mark