Closed Bug 105042 Opened 23 years ago Closed 23 years ago

PR_sscanf() is 1% of startup

Categories

(Core :: XPConnect, defect)

x86
Windows 2000
defect
Not set
normal

Tracking

()

VERIFIED FIXED

People

(Reporter: dp, Assigned: jband_mozilla)

References

Details

(Keywords: perf)

Attachments

(1 file)

PR_sscanf 1105 calls 31ms The primary caller of this is: xptiManifest::Read 99% 1077 calls 31ms Can we do some easier parsing ?
Blocks: 7251
Keywords: perf
You mean *less* easier parsing. Using PR_sscanf is easy. Writing a custom parser is a pain.
Yeah. (or) Instead of being so ultra flexible, be more restrictive in what we accept from the xpt files. After all, we are the ones writing it out too.
FWIW, this is not about xpt files. It is about xpti.dat (open it up and take a look). It is highly structured (though the fix for bug 104191 adds a bit more compexity). Writing a custom parser to handle the various data fields is completely doable. It is just yet another chunk of code sucking up valuable memory - and a pain :)
Status: NEW → ASSIGNED
Ccing dougt for review of nsCRT::atoll() The atoll() addition was not just for this. I have been wanting to use this in the component manager etc for a very long time. The dll size increased by 76 bytes.
dp! You should have said you were going to work on this. The bug was assigned to me. I wrote something similar yesterday. It is entwined with another bug fix - bug 104191. I'll attach the patch this afternoon after I get to MtView.
Sorry. I was up late last night and decide to do it (and reduce your pain!). No sweat if you are not use my changes. They didnt take a lot of time anyway plus I deserve it - I should have told you and only then worked on it. Let me know if you need atoll() or you have another. I would need it for later use too in plugins and xpcom-registry.
BTW, if would be good if you mark bug ASSIGNED and have a TFV in there.
Hey, I *did* accept the bug. Anyway, I like your atoll better than what I wrote. I was trying to avoid the 64bit (and base 10) multiply by reading and writing the 64 bit numbers in hex and scanning them in 32bit segments. What you have for that conversion is probably fine. I'll integrate it into my patch. I'll hack a little and post a patch. Thanks.
I posted my combined path to bug 104191. I used dp's nsCRT::atoll. I used my own code to unify the scanning for separators rather than the repeated calls to strchr. I also decided to store the file size field as a uint32 and assume that the high 32bits are going to be zero anyway. I've been doing my profiling with Quantify and xpcshell. xptiManifest::Read was taking over 20% of the *xpcom* startup time. With this change it takes less than 10%.
The fix for this bug went into the trunk with the fix for bug 104191. Thanks dp!
Status: ASSIGNED → RESOLVED
Closed: 23 years ago
Resolution: --- → FIXED
I do not have Quantify, etc. dp, would you be able to verify this fix for me? Is the performance better now? Thanks -
I will verify it.
dp reports that he has been able to verifiy this, so marking Verified -
Status: RESOLVED → VERIFIED
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