Squid handling of concurrent cache misses

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By : mak

Date : January 02 2021, 06:48 AM

fixed the issue. Will look into that further You're looking for collapsed forwarding: http://www.squid-cache.org/Versions/v2/2.7/cfgman/collapsed_forwarding.html
Available in 2.6 and 2.7, but not yet in 3.x.

code :

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Squid - Can I purge cache objects in squid-cache using url?

By : Hannes Müller

Date : March 29 2020, 07:55 AM

around this issue I have hosted a cgi script in cache machine which listens for http request and executes squidclient.

code :

use CGI qw(:standard); 

$urltopurge=param("url"); 

print $urltopurge;

print header(); 

print "Trying to purge <b>$urltopurge</b><P>"; 

print "sending command <B>squidclient -v -m PURGE -h 172.24.133.181 -p 8081 $urltopurge</b> to proxy server<P><HR><b>Server Response:</b><P>"; 

$result = system ("C:\\squid\\bin\\squidclient.exe -v -m PURGE -p 8081 $urltopurge"); 

print $result;

print "<hr>"; 

print "purger.cgi - Praveen";

cpu cache performance. store misses vs load misses

By : Sirius_Chan

Date : March 29 2020, 07:55 AM

seems to work fine A load-miss (as you know) is referring to when the processor needs to fetch data from main memory, but data does not exist in the cache. So whenever the processor wants some data from the main memory, it esquires the cache, and if the data is already loaded you get a load-hit and otherwise you get a load-miss.
A store-miss is related to when the processor wants to write back the newly calculated data to the main memory.When it wants to write-back the data to the main memory, it hasto make sure that the content of the cache and main memory are in sync with each other. It can happen with two different policies that you can find here: Writing Policies.

Total Cache misses fewer than data cache misses (PAPI_L1_DCM > PAPI_L1_TCM)

By : Szoko Loko

Date : March 29 2020, 07:55 AM

Hope that helps I found an explanation of the first problem. (PAPI_L1_DCM > PAPI_L1_TCM):
The referenced native event is the L1D:REPLACEMENT which "Counts the number of lines brought into the L1 data cache." source

code :

$ papi_avail -e PAPI_L1_DCM
Available PAPI preset and user defined events plus hardware information.
--------------------------------------------------------------------------------
PAPI Version             : 5.4.1.0
Vendor string and code   : GenuineIntel (1)
Model string and code    : Intel(R) Xeon(R) CPU E5-2680 v3 @ 2.50GHz (63)
CPU Revision             : 2.000000
CPUID Info               : Family: 6  Model: 63  Stepping: 2
CPU Max Megahertz        : 2501
CPU Min Megahertz        : 1200
Hdw Threads per core     : 2
Cores per Socket         : 12
Sockets                  : 2
NUMA Nodes               : 2
CPUs per Node            : 24
Total CPUs               : 48
Running in a VM          : no
Number Hardware Counters : 11
Max Multiplex Counters   : 32
--------------------------------------------------------------------------------

Event name:                   PAPI_L1_DCM
Event Code:                   0x80000000
Number of Native Events:      1
Short Description:           |L1D cache misses|
Long Description:            |Level 1 data cache misses|
Developer's Notes:           ||
Derived Type:                |NOT_DERIVED|
Postfix Processing String:   ||
 Native Code[0]: 0x40000006 |L1D:REPLACEMENT|
 Number of Register Values: 0
 Native Event Description: |L1D cache, masks:L1D Data line replacements|

--------------------------------------------------------------------------------
avail.c                                     PASSED

why is the cache-misses to instructions ratio a better indicator of cache performance compared to the cache-references t

By : Preet Gandhi

Date : March 29 2020, 07:55 AM

hope this fix your issue They're ultimately both misleading, but in different ways.
Misses to hits is interesting to know, however you can "soak" some misses by having lots of arithmetic to do while the miss is being handled. Misses to #instructions would tell you something about that, in that a very low number of misses/instruction suggests that you're in such a case. It doesn't mean you actually are though, for example if the address of the next load which misses is calculated by a long calculation that itself depends on the previous miss, then it all becomes serialized and the misses/instruction becomes a bit misleading. Even so, if it's low enough, then the total time mostly depends on the arithmetic so the misses wouldn't be a big problem.

Why does writing to file increase cache-misses and branch-misses so much?

By : Hoa Nguyen

Date : March 29 2020, 07:55 AM

I hope this helps . Without the "fout<Note that the main culprit here is endl (which forces flushing the buffers and thus triggers a system call). Replace it with '\n' and the impact on the performance should be much less.