Messages in this thread | | | From | Miguel Ojeda <> | Date | Mon, 6 Dec 2010 17:31:04 +0100 | Subject | Re: [Patch 00/15] Reduce tracing payload size. |
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On Mon, Dec 6, 2010 at 3:58 PM, Andi Kleen <andi@firstfloor.org> wrote: > On Mon, Dec 06, 2010 at 08:56:37AM -0500, Ted Ts'o wrote: >> On Mon, Dec 06, 2010 at 02:22:00PM +0100, Andi Kleen wrote: >> > David Sharp <dhsharp@google.com> writes: >> > > >> > > These patches are just a start to shrinking the size of trace events. I am >> > > planning to also make small versions of trace events that are used when >> > > CONFIG_SMALL_TRACES is enabled. I'm also open to discussion of other ways to >> > > shrink event sizes. >> > >> > Maybe the simplest would be to lzo them as they get logged? >> > I assume you already considered that? >> >> The tracing subsystem is supposed to be extremely low-overhead. >> Compressiong the event log would add considerable CPU overhead. If we > > lzo as a rule of thumb is about as expensive as 3x memcpy() > That's not really expensive.
That is true for the decompression step but not for the compression one, which takes more than 10 memcpys().
> > -Andi > > -- > ak@linux.intel.com -- Speaking for myself only. > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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